The sluicing flume that was designed is less capable of silting up and losing its calibration than its counterparts of standard sharp-crested compound weir design. The laboratory work described here led to a refinement in the design in the form of a short flume set into the lowest section of a compound Crump weir gauging installation. Critical flow occurs near the exit of this flume, and it is ...

The present day distribution and spatial genetic diversity of Mesoamerican biota reflects a long history of responses to habitat change. The hummingbird Lampornis amethystinus is distributed in northern Mesoamerica, with geographically disjunct populations. Based on sampling across the species range using mitochondrial DNA (mtDNA) sequences and nuclear microsatellites jointly analysed with phen...

erosion is one of the important factors in soil degradation and decrease fertility and slope length is one of the most effective factors in land form and amount of erosion. the objective of this study was investigation of spatially variation of sediment concentration in slope length until to receive transport capacity. to obtain this goal a hill slope simulator system designed and manufactured....

Aploparaksis borealis sp. n. (Cestoda: Hymenolepididae), from the long-tailed jaeger, Stercorarisu longicaudus Vieillot, on the Seward Peninsula, Alaska, and from the red-throated pipit, Anthus cervinus (Pallas), and the Lapland longspur, Calcarius lapponicus (Linnaeus), in Chukotka, northestern Siberia, is described. This cestode is distinguished by the structure of the cirrus and other morpho...

The interaction and hierarchy of celestial and magnetic compass cues used by migratory songbirds for orientation has long been the topic of an intense debate. We have previously shown that migratory Savannah sparrows, Passerculus sandwichensis, use polarized light cues near the horizon at sunrise and sunset to recalibrate their magnetic compass. Birds exposed to a +/-90 deg. shifted artificial ...

To explore the evolutionary consequences of climate-induced fluctuations in distribution of rainforest habitat we contrasted demographic histories of divergence among three lineages of Australian rainforest endemic skinks. The red-throated rainbow skink, Carlia rubrigularis, consists of morphologically indistinguishable northern and southern mitochondrial DNA (mtDNA) lineages that are partially...

Oxidative stress is an unavoidable consequence of metabolism and increases during intensive exercise. This is especially problematic for migratory birds that metabolize fat to fuel long-distance flight. Birds can mitigate damage by increasing endogenous antioxidants (e.g. uric acid) or by consuming dietary antioxidants (e.g. tocopherol). During flight, birds may increase protein catabolism of l...

Vocal traits can be sexually selected to reflect male quality, but may also evolve to serve additional signaling functions. We used a long-term dataset to examine the signaling potential of song in dimorphic white-throated sparrows (Zonotrichia albicollis). We investigated whether song conveys multifaceted information about the vocalizing individual, including fitness, species identity, individ...