Further Consideration of the Phylogeny of Some "Traditional" Heterotrichs (Protista, Ciliophora) of Uncertain Affinities, Based on New Sequences of the Small Subunit rRNA Gene

ABSTRACT. The systematic relationships and taxonomic positions of the traditional heterotrich genera Condylostentor, Climacostomum, Fabrea , Folliculina, Peritromus , and Condylostoma , as well as the licnophorid genus Licnophora , were re-examined using new data from sequences of the gene coding for small subunit ribosomal RNA. Trees constructed using distance-matrix, Bayesian inference, and maximum-parsimony methods all showed the following relationships: (1) the "traditional" heterotrichs consist of several paraphyletic groups, including the current classes Heterotrichea, Armophorea and part of the Spirotrichea; (2) the class Heterotrichea was confirmed as a monophyletic assemblage based on our analyses of 31 taxa, and the genus Peritromus was demonstrated to be a peripheral group; (3) the genus Licnophora occupied an isolated branch on one side of the deepest divergence in the subphylum Intramacronucleata and was closely affiliated with spirotrichs, armophoreans, and clevelandellids; (4) Condylostentor , a recently defined genus with several truly unique morphological features, is more closely related to Condylostoma than to Stentor ; (5) Folliculina, Eufolliculina , and Maristentor always clustered together with high bootstrap support; and (6) Climacostomum occupied a paraphyletic position distant from Fabrea , showing a close relationship with Condylostomatidae and Chattonidiidae despite of modest support.     

Relationships of subalpine forest fires in the Colorado Front Range with interannual and multidecadal‐scale climatic variation

Aim An understanding of past relationships between fire occurrence and climate variability will help to elucidate the implications of climate‐change scenarios for future patterns of wildfire. In the present study we investigate the relationships between subalpine‐zone fire occurrence and climate variability and broad‐scale climate patterns in the Pacific and Atlantic Oceans at both interannual and multidecadal time‐scales. Location The study area is the subalpine zone of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa), and lodgepole pine (Pinus contorta) in the southern sector of the Rocky Mountain National Park, which straddles the continental divide of the northern Colorado Front Range. Methods We compared years of widespread fire from AD 1650 to 1978 for the subalpine zone of southern Rocky Mountain National Park, with climate variables such as measures of drought, and indices such as the El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Atlantic Multidecadal Oscillation (AMO). Results Years of extensive subalpine‐zone fires are significantly related to climate variability, phases of ENSO, the PDO, and the AMO, as well as to phase combinations of ENSO, the PDO, and the AMO at both interannual and centennial time‐scales. Main conclusions Years of extensive fires are related to extreme drought conditions and are significantly related to the La Niña phase of ENSO, the negative (cool) phase of the PDO, and the positive (warm) phase of the AMO. The co‐occurrence of the phase combination of La Niña‐negative PDO‐positive AMO is more important to fire occurrence than the individual influences of the climate patterns. Low‐frequency trends in the occurrence of this combination of climate‐pattern phases, resulting from trends in the AMO, are the primary climate pattern associated with periods of high fire occurrence (1700–89 and 1851–1919) and a fire‐free period (1790–1850). The apparent controlling influence of the AMO on drought and years of large fires in the subalpine forests of the Colorado Front Range probably applies to an extensive area of western North America.     

Interplay Between Side Chain Pattern,Polymer Aggregation,and Charge Carrier Dynamics in PBDTTPD:PCBM Bulk‐Heterojunction Solar Cells

Poly(benzo[1,2‐b:4,5‐b′]dithiophene–alt–thieno[3,4‐c]pyrrole‐4,6‐dione) (PBDTTPD) polymer donors with linear side‐chains yield bulk‐heterojunction (BHJ) solar cell power conversion efficiencies (PCEs) of about 4% with phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) as the acceptor, while a PBDTTPD polymer with a combination of branched and linear substituents yields a doubling of the PCE to 8%. Using transient optical spectroscopy it is shown that while the exciton dissociation and ultrafast charge generation steps are not strongly affected by the side chain modifications, the polymer with branched side chains exhibits a decreased rate of nongeminate recombination and a lower fraction of sub‐nanosecond geminate recombination. In turn the yield of long‐lived charge carriers increases, resulting in a 33% increase in short circuit current (J _sc). In parallel, the two polymers show distinct grazing incidence X‐ray scattering spectra indicative of the presence of stacks with different orientation patterns in optimized thin‐film BHJ devices. Independent of the packing pattern the spectroscopic data also reveals the existence of polymer aggregates in the pristine polymer films as well as in both blends which trap excitons and hinder their dissociation.     

Flight songs of Dusky Flycatchers: a response to bird‐hunting raptors?

ABSTRACT.   Flight-song displays usually include distinctive vocalizations and behaviors that are probably energetically expensive and also likely to attract the attention of aerial predators. We observed flight songs performed by Dusky Flycatchers ( Empidonax oberholseri ) in two breeding populations. During 15 yr at Tioga Pass, California, we observed the display twice and, during 9 yr at Steamboat Mountain, British Columbia, we observed 21 flight-song displays. These displays were generally observed later in the breeding season, suggesting that they were not used for courtship, mate attraction, or territory defense. However, for 83% of these displays, a raptor was observed to be present, usually either an American Kestrel ( Falco sparverius ) or a Sharp-shinned Hawk ( Accipiter striatus ). We hypothesize that these displays, like stotting or other pursuit-deterrent signals, may be directed at small raptors that represent a greater threat to Dusky Flycatchers and might deter attack by signaling awareness. However, because only males were observed performing flight-song displays, it is also possible that these displays serve to alert mates and offspring about the presence of an aerial predator and reduce their vulnerability to attack.     

A perspective on positive relationships between genetic diversity and abundance in fishes

Given over 90 combined years in academic and professional activities related to genetics and fishery management (FU 57, JS 36—see Waples et al. 2008 ), we are pleased to provide an invited perspective generated by the interesting and useful article of McCusker & Bentzen (2010) . These authors reaffirm the apparent signature of neutrality of mitochondrial and microsatellite markers through an exhaustive analysis of archived genotypic data for 105 marine and freshwater fishes. They note that their conclusions are consistent with earlier and less comprehensive analyses and that they do not exclude the operation of some selective activity (e.g. genetic ‘draft’), which may be overwhelmed by N_e‐related stochastic processes. Here, we provide a complementary focus, recalling relevant issues related to neutrality and selection in applications of molecular variations in fishery management.     

山西崦山自然保护区侧柏群落优势种群种间关系分析

在样方调查的基础上,采用方差比率法、Fisher精确检验、Jaccard指数和Spearman秩相关系数研究了山西阳城崦山自然保护区侧柏群落优势种群的种间关系。结果表明：（1）群落优势种总体呈正关联,但关联性较弱,种的分布具有相对独立性。（2）Fisher精确检验与Jaccard指数结合使用可以取得较好的研究结果。（3）Jaccard指数结果表明在乔、灌、草各层中占据明显优势地位的种群其种间联结程度较大。（4）根据研究结果把侧柏群落的优势种群划分为3个生态种组：白皮松生态种组、侧柏生态种组和白莲蒿生态种组。