scholarly journals Cerulean warbler relative abundance and frequency of occurrence relative to large-scale edge

2003 ◽  
Author(s):  
Scott B. Bosworth
Keyword(s):  
Relative Abundance ◽  
Large Scale ◽  
Frequency Of Occurrence ◽  
Cerulean Warbler

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Relative Abundance ◽  
Mississippi River ◽  
Largemouth Bass ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Micropterus Salmoides ◽  
Lepomis Macrochirus ◽  
Large River ◽  
Frequency Of Occurrence ◽  
Abundance And Distribution

<em>Abstract.</em>—An investigation of historical fisheries information for pools 4–13 of the upper Mississippi River (UMR) was conducted to 1) determine the pre-1938 relative abundance and distribution of bluegill <em>Lepomis macrochirus </em>and largemouth bass <em>Micropterus salmoides, </em>2) determine the composition and relative abundance of the preimpoundment fish assemblage, and 3) determine if a shift in frequency of occurrence and relative abundance has occurred due to impoundment.

scholarly journals The role of the observed tropical convection in the generation of frost events in the southern cone of South America

2008 ◽  
Vol 26 (6) ◽  
pp. 1379-1390 ◽  
Author(s):  
G. V. Müller ◽  
T. Ambrizzi ◽  
S. E. Ferraz
Keyword(s):  
South America ◽  
Large Scale ◽  
Rossby Waves ◽  
Tropical Convection ◽  
The Other ◽  
Linear Wave ◽  
Frequency Of Occurrence ◽  
The South ◽  
Cold Events ◽  
Extreme Cold

Abstract. Based on previous results obtained from observations and linear wave theory analysis, the hypothesis that large-scale patterns can generate extreme cold events in southeast South America through the propagation of remotely excited Rossby waves was already suggested. This work will confirm these findings and extend their analysis through a series of numerical experiments using a primitive equation model where waves are excited by a thermal forcing situated in positions chosen according to observed convection anomalies over the equatorial region. The basic state used for these experiments is a composite of austral winters with maximum and minimum frequency of occurrence of generalized frosts that can affect a large area known as the Wet Pampas located in the central and eastern part of Argentina. The results suggest that stationary Rossby waves may be one important mechanism linking anomalous tropical convection with the extreme cold events in the Wet Pampas. The combination of tropical convection and a specific basic state can generate the right environment to guide the Rossby waves trigged by the tropical forcing towards South America. Depending on the phase of the waves entering the South American continent, they can favour the advection of anomalous wind at low levels from the south carrying cold and dry air over the whole southern extreme of the continent, producing a generalized frost in the Wet Pampa region. On the other hand, when a basic state based on the composites of minimum frosts is used, an anomalous anticyclone over the southern part of the continent generates a circulation with a south-southeast wind which brings maritime air and therefore humidity over the Wet Pampas region, creating negative temperature anomalies only over the northeastern part of the region. Under these conditions even if frosts occur they would not be generalized, as observed for the other basic state with maximum frequency of occurrence of generalized frosts.

Lower and Middle Devonian brachiopod-dominated communities of Nevada, and their position in a biofacies-province-realm model

1990 ◽  
Vol 64 (6) ◽  
pp. 902-941 ◽  
Author(s):  
J. G. Johnson ◽  
G. Klapper ◽  
J. G. Johnson
Keyword(s):  
Relative Abundance ◽  
Middle Devonian ◽  
Large Scale ◽  
Carbonate Platform ◽  
Specific Content ◽  
Sea Level Fluctuations ◽  
Community Associations ◽  
Key Species ◽  
Platform Margin ◽  
Conodont Zone

Lower and Middle Devonian brachiopod-dominated communities of Nevada are numerous (46) and most are positioned on or adjacent to the carbonate-platform foreslope or ramp. Level-bottom community chains are fundamentally different from community associations that are interrupted by a platform margin. All communities require relative abundance data of constituent species for recognition. These communities prove to be endemic to the Nevada-southeastern California area, even though faunal similarities with distant regions in North America can be recognized. Analogous communities, the same age as comparable communities in Nevada, differ in overall specific content and in relative abundance of diagnostic species. Identification of analogous communities requires recognition of common physical environments (first) and faunal similarity (second). Groupings of communities based on presence-absence data of key species and genera are not meaningful.Biofacies boundaries sited on carbonate-platform foreslopes separate community associations and also act as filter boundaries for faunal realms. The platform and peripheral biofacies thus delineated are also realms, a pattern that is repeated by different organisms from Cambrian to Cenozoic. Biofacies boundaries shift in concert with large-scale sea-level fluctuations. During platform emergence, most faunas are peripheral and therefore cosmopolitan. Transgression initially forms small, isolated epeiric seas populated from offshore, and endemic faunas evolve. Increased transgression merges epeiric seas and faunas, reducing provinciality and diversity through competition. Regression results in extinctions in proportion to its rate and the area involved. The cycle repeats.Thehermanni-cristatusconodont Zone is replaced with the namehermanniZone. ThedisparilisZone is divided into Lower and Upper Subzones. ThenorrisiZone is proposed at the top of the Middle Devonian.

scholarly journals Binning unassembled short reads based on k-mer abundance covariance using sparse coding

GigaScience ◽  
2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Olexiy Kyrgyzov ◽  
Vincent Prost ◽  
Stéphane Gazut ◽  
Bruno Farcy ◽  
Thomas Brüls
Keyword(s):  
Relative Abundance ◽  
Sparse Coding ◽  
Large Scale ◽  
Computational Cost ◽  
Joint Analysis ◽  
Short Reads ◽  
Elastic Net Regularization ◽  
Sparse Dictionary Learning ◽  
Metagenome Assembly ◽  
Low Levels

Abstract Background Sequence-binning techniques enable the recovery of an increasing number of genomes from complex microbial metagenomes and typically require prior metagenome assembly, incurring the computational cost and drawbacks of the latter, e.g., biases against low-abundance genomes and inability to conveniently assemble multi-terabyte datasets. Results We present here a scalable pre-assembly binning scheme (i.e., operating on unassembled short reads) enabling latent genome recovery by leveraging sparse dictionary learning and elastic-net regularization, and its use to recover hundreds of metagenome-assembled genomes, including very low-abundance genomes, from a joint analysis of microbiomes from the LifeLines DEEP population cohort (n = 1,135, &gt;1010 reads). Conclusion We showed that sparse coding techniques can be leveraged to carry out read-level binning at large scale and that, despite lower genome reconstruction yields compared to assembly-based approaches, bin-first strategies can complement the more widely used assembly-first protocols by targeting distinct genome segregation profiles. Read enrichment levels across 6 orders of magnitude in relative abundance were observed, indicating that the method has the power to recover genomes consistently segregating at low levels.

Response of Breeding Songbirds to Vegetation Management in Conifer Plantations Established in Boreal Mixedwoods

2011 ◽  
Vol 87 (02) ◽  
pp. 217-224 ◽  
Author(s):  
Gregory Zimmerman ◽  
F. Wayne Bell ◽  
John Woodcock ◽  
Aaron Palmer ◽  
Jorma Paloniemi
Keyword(s):  
Relative Abundance ◽  
Aerial Photography ◽  
Large Scale ◽  
Bird Species ◽  
Vegetation Management ◽  
Post Treatment ◽  
Conifer Plantations ◽  
Boreal Mixedwoods ◽  
Proportional Cover

We examined the response of breeding songbird communities 11 years after four vegetation management treatments were applied. Post-treatment vegetation was characterized by manually interpreting large-scale aerial photography and estimating proportional cover of eight vegetation classes. Songbird abundance was assessed by territory mapping. Using GIS layers, number of registrations and average vegetation proportions were compared among treatments. Ordination of the relative abundance of the 11 most frequent bird species suggested differences between Vision® and untreated areas. These results show that effects of vegetation management on songbirds may be more persistent than previous studies suggest and that monitoring should continue.

scholarly journals Spatial organization of krill and seabirds in the central California Current

2011 ◽  
Vol 68 (7) ◽  
pp. 1391-1402 ◽  
Author(s):  
Jarrod A. Santora ◽  
Stephen Ralston ◽  
William J. Sydeman
Keyword(s):  
Relative Abundance ◽  
Large Scale ◽  
Spatial Organization ◽  
Marine Ecosystem ◽  
California Current ◽  
Habitat Associations ◽  
Ecosystem Dynamics ◽  
Seabird Species ◽  
Central California ◽  
Shelf Slope

AbstractSantora, J. A., Ralston, S., and Sydeman, W. J. 2011. Spatial organization of krill and seabirds in the central California Current. – ICES Journal of Marine Science, 68: 1391–1402. The hypothesis that krill and krill–predator spatial organization and abundance co-vary interannually was tested by investigating the spatial organization of krill and planktivorous seabirds in the central California Current ecosystem over 5 years of varying oceanographic conditions, 2002–2006. To measure the abundance and distribution of krill, data were integrated from large-scale hydroacoustic surveys and station-based net samples, and these data linked to concurrent shipboard visual surveys of seabirds. Acoustically based estimates of the relative abundance of krill were correlated with net samples of Euphausia pacifica, suggesting that acoustic signals mainly reflected the distribution of this numerically dominant species. The distribution and abundance of krill displayed marked changes over years, but the characteristic spatial scale of krill and seabirds remained similar (1–4 nautical miles), confirming the hypothesis of covariance in spatial structure. Krill and the seabird species investigated showed similar habitat associations, i.e. the outer shelf and shelf–slope region, showing that the at-sea distributions of seabirds can provide information on the presence/absence of krill patches. The results also underscore the importance of measuring spatial organization as well as relative abundance in promoting better understanding of predator–prey and marine ecosystem dynamics.

scholarly journals Impact of Island-Induced Clouds on Surface Measurements: Analysis of the ARM Nauru Island Effect Study Data

2005 ◽  
Vol 44 (7) ◽  
pp. 1045-1065 ◽  
Author(s):  
Sally A. McFarlane ◽  
Charles N. Long ◽  
Donna M. Flynn
Keyword(s):  
Program Analysis ◽  
Large Scale ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Surface Radiation ◽  
Shortwave Radiation ◽  
Atmospheric Radiation ◽  
Frequency Of Occurrence ◽  
Low Cloud ◽  
Surface Measurements

Abstract An Atmospheric Radiation and Cloud Station (ARCS) was established on the island of Nauru by the Atmospheric Radiation Measurement (ARM) Program. Analysis of the Nauru99 field experiment data indicated that measurements at the ARCS were affected by a cloud plume that was induced by diurnal heating of the island. During the Nauru Island Effects Study, instrumentation was installed at a second site to develop criteria for identifying when the cloud plume occurs and to quantify its effect on ARCS measurements. The plume directional heading and frequency of occurrence are affected by the large-scale tropical circulation. During the present study, in which an El Niño was developing, Nauru was in a region of active convection, and easterly trade winds were not dominant; plumes were observed in 25% of satellite images, and only one-half of the observed plumes were downwind of the ARCS site. Surface wind direction, surface air temperature, and downwelling solar radiation at the two sites were used to identify periods when the cloud plume affected surface measurements. Differences in low-cloud frequency and surface radiation between plume-affected and non-plume-affected periods were examined. Existence of the cloud plume increased the average low-cloud frequency of occurrence from 20% to 35%, decreased the average downwelling shortwave radiation by 50–60 W m−2, and increased the average downwelling longwave radiation by 5–10 W m−2. Installing a suite of surface meteorological instruments and a global shortwave radiometer at a second site will allow for the long-term quantification of the cloud plume effect on the radiation field at the ARCS site.

Predictability of large scale drivers leading intense Mediterranean cyclones

2020 ◽  
Author(s):  
M. Carmen Alvarez-Castro ◽  
Silvio Gualdi ◽  
Pascal Yiou ◽  
Mathieu Vrac ◽  
Robert Vautard ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Human Life ◽  
Heavy Precipitation ◽  
Mediterranean Area ◽  
Frequency Of Occurrence ◽  
Large Scale Circulation ◽  
Mediterranean Cyclones ◽  
Circulation Patterns ◽  
Anthropogenic Forcings

&lt;p&gt;Windstorms, extreme precipitations and instant floods seems to strike the Mediterranean area with increasing frequency. These events occur simultaneously during intense tropical-like Mediterranean cyclones. These intense Mediterranean cyclones are frequently associated with wind, heavy precipitation and changes in temperature, generating high risk situations such as flash floods and large-scale floods with significant impacts on human life and built environment. Although the dynamics of these phenomena is well understood, little is know about their climatology. It is therefore very difficult to make statements about the frequency of occurrence and its response to climate change. Thus, intense Mediterranean cyclones have many different physical aspects that can not be captured by a simple standard approach.&amp;#160;&lt;/p&gt;&lt;p&gt;The first challenge of this work is to provide an extended catalogue and climatology of these phenomena by reconstructing a database of intense Mediterranean cyclones dating back up to 1969 using the satellite, the literature and reanalyses. Applying a method based on dynamical systems theory we analyse and attribute their future changes under different anthropogenic forcings by using future simulations within CMIP framework. Preliminary results show a decrease of the large-scale circulation patterns favoring intense Mediterranean cyclones in all the seasons except summer.&lt;/p&gt;

scholarly journals Application of 3-nitrooxypropanol and canola oil to mitigate enteric methane emissions of beef cattle results in distinctly different effects on the rumen microbial community

2021 ◽  
Author(s):  
Robert J Gruninger ◽  
Xiu Min Zhang ◽  
Megan L. Smith ◽  
Limin Kung ◽  
Diwakar Vyas ◽  
...  
Keyword(s):  
Microbial Community ◽  
Beef Cattle ◽  
Relative Abundance ◽  
Canola Oil ◽  
Large Scale ◽  
Control Diet ◽  
Gas Production ◽  
Ruminal Fermentation ◽  
Volatile Fatty Acid Concentration ◽  
Enteric Methane

Abstract Background: The major GHG from ruminants is enteric methane (CH4) which in 2010, was estimated at 2.1 Gt of CO2 equivalent, accounting for 4.3% of global GHG emissions. There re extensive efforts being made around the world to develop methane mitigating inhibitors that specifically target rumen methanogens with the ultimate goal of reducing the environmental footprint of ruminant livestock production. This study examined the individual and combined effects of supplementing a high-forage diet (90% barley silage) fed to beef cattle with the investigational methane (CH4) inhibitor 3-nitrooxypropanol (3-NOP) and canola oil (OIL) on the rumen microbial community in relation to enteric CH4 emissions and ruminal fermentation.Results: 3-NOP and OIL individually reduced enteric CH4 emission (-28.2% and -24.0%, respectively), and the effects were additive when used in combination (-51.3%). 3-NOP increased H2 emissions 37 fold, while co-administering 3-NOP and OIL increased H2 in the rumen 20-fold relative to the control diet. The inclusion of 3-NOP or OIL reduced the diversity of the rumen microbiome. 3-NOP resulted in targeted changes in the microbiome decreasing the relative abundance of Methanobrevibacter and increasing the relative abundance of Bacteroidetes. The inclusion of OIL resulted in large scale changes to the microbial community that were associated with changes in ruminal volatile fatty acid concentration and gas production. OIL significantly reduced the abundance of protozoa and fiber-degrading microbes in the rumen but it did not selectively alter the abundance of rumen methanogens.Conclusions: Our data provide a mechanistic understanding of CH4 inhibition by 3-NOP and OIL when fed alone and in combination to cattle. 3-NOP specifically targeted rumen methanogens inhibiting the hydrogenotrophic methanogenesis pathway and resulting in increased H2 emissions and propionate production. In contrast, OIL caused large scale changes in the rumen microbial community by indiscriminately altering the abundance of a range of rumen microbes, reducing the abundance of fibrolytic bacteria and altering rumen fermentation. Importantly, our data suggests that co-administering CH4 inhibitors with distinct mechanisms of action can both enhance CH4 inhibition and provide alternative sinks to prevent excessive accumulation of ruminal H2.

scholarly journals Feeding habits of Aspitrigla cuculus (L., 1758) (red gurnard), Lepidotrigla cavillone (Lac., 1802) (large scale gurnard) and Trigloporus lastoviza (Brunn., 1768) (rock gurnard) around Cyclades and Dodecanese Islands (E. Mediterranean)

2000 ◽  
Vol 1 (1) ◽  
pp. 91 ◽  
Author(s):  
A. TERRATS ◽  
G. PETRAKIS ◽  
C. PAPACONSTANTINOU
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Bottom Trawling ◽  
Percentage Frequency ◽  
Index Of Relative Importance

The feeding habits of the three most abundant gurnard species, red gurnard (Aspitrigla cuculus), large scale gurnard (Lepidotrigla cavillone) and rock gurnard (Trigloporus lastoviza) in the eastern Mediterranean (Dodecanese and Cyclades, Greece) are examined. The stomach contents of the gurnard specimens collected in April and September 1996 by bottom trawling were analyzed. The % frequency of occurrence, % number and % weight of prey types in the stomach contents were evaluated. By weight, Mysidacea and Decapoda dominated in the diet of the three species in both seasons, however the Index of Relative Importance, as well as the percentage frequency of occurrence varied. Rock gurnard presented the most diverse diet whereas the diet of large scale and red gurnard were more specialized. High overlap in terms of number was found between rock and large scale gurnard in May. Rock gurnard had the most divers diet in both seasons.

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