bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution, habitat and adaptability of the genusTapirus
Authors: GARCÍA Manolo J. , MEDICI Emília Patrícia , NARANJO Eduardo J. , NOVARINO Wilson , LEONARDO Raquel S.
Published: August 2012

In this manuscript, as a starting point, the ancient and current distribution of the genusTapirusare summarized, from its origins, apparently in Europe, to current ranges. Subsequently, original and current tapir habitats are described, as well as changes in ancient habitats. As the manuscript goes on, we examine the ways in which tapir species interact with their habitats and the main aspects of habitat use, spatial ecology and adaptability. Having reviewed the historic and current distribution of tapirs, as well as their use and selection of habitats, we introduce the concept of adaptability, considering that some of the tapir physiological characteristics and behavioral strategies can reduce the negative impact of habitat alteration and climate change. Finally, we provide recommendations for future research priorities. The conservation community is still missing important pieces of information for the effective conservation of tapirs and their remaining habitats in Central and South America and Southeast Asia. Reconstructing how tapir species reached their current distribution ranges, interpreting how they interact with their habitats and gathering information regarding the strategies they use to cope with habitat changes will increase our understanding about these animals and contribute to the development of conservation strategies.
Linkage disequilibrium and effective population size when generations overlap
Authors: Robinson John D. , Moyer Gregory R.
Published: August 2012

Estimates of effective population size are critical for species of conservation concern. Genetic datasets can be used to provide robust estimates of this important parameter. However, the methods used to obtain these estimates assume that generations are discrete. We used simulated data to assess the influences of overlapping generations on the estimates of effective size provided by the linkage disequilibrium (LD) method. Our simulations focus on two factors: the degree of reproductive skew exhibited by the focal species and the generation time, without considering sample size or the level of polymorphism at marker loci. In situations where a majority of reproduction is achieved by a small fraction of the population, the effective number of breeders can be much smaller than the per‐generation effective population size. The LD in samples of newborns can provide estimates of the former size, while our results indicate that the latter size is best estimated using random samples of reproductively mature adults. Using samples of adults, the downwards bias was less than approximately 15% across our simulated life histories. As noted in previous assessments, precision of the estimate depends on the magnitude of effective size itself, with greater precision achieved for small populations.
mmod: an R library for the calculation of population differentiation statistics
Authors: Winter David J.
Published: August 2012

mmod is a library for the R programming language that allows the calculation of the population differentiation measures Dest, G″ST and φ′ST. R provides a powerful environment in which to conduct and record population genetic analyses but, at present, no R libraries provide functions for the calculation of these statistics from standard population genetic files. In addition to the calculation of differentiation measures, mmod can produce parametric bootstrap and jackknife samples of data sets for further analysis. By integrating with and complimenting the existing libraries adegenet and pegas, mmod extends the power of R as a population genetic platform.
Comparison of corneal thickness and curvature in myopic and keratoconic eyes of patients from French Caribbean Isles and continental France
Authors: Joyaux Jean Christophe , Gallois Anne , Touboul David , Delcourt Cécile , Colin Joseph , Patel Sudi
Published: August 2012

Purpose:  To evaluate the corneal thickness and curvature of myopic and patients with keratoconus from two countries.

Methods:  This cross‐sectional study was conducted at Cabinet Opale, Fort de France, French West Indies and University Hospital of Bordeaux, France. Corneal thickness and curvature were assessed in 170 keratoconic eyes of 89 residents of the French Caribbean Islands (FCI) and 159 keratoconic eyes of 91 residents of the Aquitaine region of southwest France. A group of age‐matched keratoconus‐free patients who had been referred for refractive surgery owing to myopia (173 FCI [173 eyes; 87 individuals] and Aquitaine [181 eyes; 93 individuals]) were also assessed.

Results:  The mean age at keratoconus diagnosis was significantly higher among FCI than Aquitaine residents (p = 0.009). The mean keratometric (Km) reading was statistically higher for keratoconic FCI than Aquitaine patients, at 48.06 versus 46.21 diopters (p = 0.001). This difference was more pronounced among patients aged >40 years than those ≤40 years (p = 0.009). Patients with keratoconus showed no significant difference in mean central corneal thickness and thinnest corneal point values, irrespective of region. Myopic individuals from the FCI, however, had significantly lower mean central corneal thickness and thinnest corneal point measurements than Aquitaine myopics, irrespective of age group (p ≤ 0.0008).

Conclusion:  The corneas of patients with keratoconus of African‐Caribbean and Caucasian origins are of similar thickness. Myopic African‐Caribbean patients referred for refractive surgery tend to present with thinner corneas than Caucasians.
The Tragedy of the Atmospheric Commons: Discounting Future Costs and Risks in Pursuit of Immediate Fossil‐Fuel Benefits
Authors: Murphy Raymond , Murphy Maya
Published: August 2012

Une des plus significatives approches positives à la politique du changement climatique sur l’échelle exigée par le problème est celle de Giddens. Cet article étale des faiblesses dans son argument et découvre les motivations divergentes pour l'atténuation des émissions et la sécurité énergétique au Canada ainsi qu'en Nouvelle Zélande, contrairement à ce qui s'est passé en Europe du Nord sur lequel Giddens a basé son analyse. Ceci suggère que la réponse au changement climatique varie selon des structures culturelles et géophysiques plus profondes. Cet article examine aussi l'analyse coûts(risques)‐bénéfices versus le principe de précaution, la directionnalité de la convergence politico‐économique avec l'atténuation, et la partisannerie politique au sujet du changement climatique. Il démontre la complexité de faire converger les opportunités économiques immédiates avec l'atténuation du mal éloigné.
Performance et relations de conseil: comment la structure relationnelle de l’élite des chercheurs français en cancérologie a conditionné leur progression entre 1999–2001 et 1996–1998
Authors: Barré Germain , Lazega Emmanuel , Jourda Marie‐Thérèse
Published: August 2012

Cet article montre que les performances des chercheurs français en cancérologie sont conditionnées par leur réseau de conseils. Ils progressent s'ils maximisent l'accès à certaines ressources rares (et leurs connexion à d'autres groupes que le leur dans certains cas). L'absence de concurrence de statut à l'intérieur du groupe de pairs est un avantage comme une ouverture relationnelle suffisante en dehors de son groupe avec une majorité de chercheurs “dépendants”. En tenant compte d'une forme de plafond de verre et d'une régulation spécifique aux hématologues, les chercheurs disposant des bonnes qualités structurales sont onze fois plus nombreux à progresser.
Thermal State and Strength of the Lithosphere Beneath the Chinese Mainland
Authors: Yang WANG
Published: August 2012

The temperature distributions of the lithosphere underneath the mainland of China were estimated by applying local isostatic equilibrium‐constrained geothermal calculations. Maps of the lateral temperature variation at depths of 40, 70, and 100 km are presented for the whole Chinese continent, with the thermal thickness of the lithosphere is calculated. Lithospheric roots of 160–200 km thickness underlie Tarim and the Upper Yangtze platform, but are absent beneath the entire Sino‐Korean platform. In general, the Tibetan plateau and fold belts to the north have warm but thick lithospheres, whereas thinner thermal lithospheres have been identified in northern Tibet and central Tian Shan around Issyk‐Kul Lake. The warm and soft lithosphere in the Tibetan plateau and Tian Shan are caused by uniform north‐south shortening, which may represent a snapshot of the early stage of convective thinning of the convergent lithosphere. However, the lithospheric thinning beneath northeastern China might be related to volatile infiltration by dehydration of the deeply subducting Pacific slab during the Cenozoic. Dry and wet upper mantle rheology display “jelly sandwich” and “crème brûlée” pictures, respectively, demonstrating the mechanical behaviour of the Chinese lithosphere outside the Tibetan plateau. Considering a more geologically evident wet‐mantle rheology, the “crème brûlée” model can approximate the lithospheric rheology for the most earthquake‐prone regions on the Chinese mainland.
Geochemical Features and Metallogenic Prediction of the Caixiashan‐Weiquan Area in the East Tianshan Region
Authors: Lu LU , Lixin ZHU , Keyan XIAO , Shengming MA , Jiangning YIN , Mingzuan XU
Published: August 2012

The Caixiashan‐Weiquan area is an important ore concentration area in the eastern Tianshan metallogenic belt. Firstly, this paper studies geochemical features of 1564 samples of 1:200000 stream sediments of the Matoutan mapsheet, where the Caixiashan and Weiquan deposits are located. Processing, analysis and explanation of exploration geochemical data play an important role in the procedure of finding the ore, which are related to whether the measured elements content of geochemical samples can effectively guide the work of mineral exploration. As a highly nonlinear dynamical system, the neural network is more analogous to the human brains in terms of principles and features compared with conventional geochemical approaches. It can adapt itself to the environment, sum up laws, complete pattern recognition. Secondly, the authors used the Kohonen neural network to classify all samples based on 10 mineralization elements of stream sediment samples in order to determine possible mineral ores, reduce the scope of ore targets and study indicator elements of the ninth group of samples, which is the mostly closest to the deposit The results show that the neural network can delineate metallogenic prospective areas and is effective in the discovery of deep geochemical information.
Combination Patterns and Depositional Characteristics of Ordovician Carbonate Banks in the Western Tarim Basin, China
Authors: Xiaolan HU , Tailiang FAN , Zhiqian GAO , Bingsong YU , Xiaozhi CHEN , Hongyu WANG , Jianping WANG , Rangbin LI , Meng DING , Yifan LI
Published: August 2012

The combination patterns and depositional characteristics of the carbonate banks are investigated based on outcrop sections, thin sections, and carbon isotopes of Ordovician in the western Tarim Basin, China. Four carbonate bank combination patterns are deposited in the Ordovician, western Tarim Basin, including: Reef‐Bank Complex (RBC), Algae‐Reef‐Bank Interbed (ARBI), Thick‐Layer Cake Aggradation Bank (TLCAB), and Thin‐Layer Cake Retrogradation Bank (TLCRB). All combination patterns show clear periods vertically. The RBC is mainly composed of reefs and bioclastic banks, and the dimension of the RBC depends on the scale of the reefs. Bioclastic banks deposits surround the reefs. The range of the ARBI is determined by the scale of algae‐reefs, algae peloid dolomite microfacies and algal dolomite microfacies deposit alternating vertically. TLCAB and TLCRB are deposited as layer‐cakes stacking in cycles and extending widely with cross bedding developed. The grains of TLCAB and TLCRB are diverse and multi‐source. With the impacting of relative sea level change, biological development and geomorphology, the ARBI, TLCAB or TLCRB, RBC are successively developed from the Lower Ordovician Penglaiba Formation to the Middle Ordovician Yijianfang Formation. The depositional environment analysis of Ordovician indicates that the RBC and ARBI can form effective oil and gas reservoirs, and the TLCAB and TLCRB have the potential to form the huge scale oil and gas reservoirs and to be the crucial targets of exploration for the Ordovician carbonate banks in the future.
Sedimentary Characteristics of the Pleistocene Outwash Accumulation and their Implications for Paleoclimate Change in the Midstream of Dadu River, Southwestern China
Authors: Guoxiang TU , Runqiu HUANG , Hui DENG , Yanrong LI
Published: August 2012

Ancient outwash accumulations, deposited in Pleistocene with complicated sedimentary characteristics, are discovered in the midstream valley of Dadu River, Southwestern China. Their sedimentation characteristics are investigated for gaining a deep insight into the dependency of Paleoclimate changes in this area. This is achieved by means of detailed site investigation, sampling and laboratory tests (grain size distribution and Electron Spin Resonance dating tests) for two representative outwash accumulations. Based on the present study, several main conclusions are drown out as follows: 1) The accumulations are composed mainly of coarse soils (coarse fraction is over 50%) and very coarse soils (coarse fraction is about 20%–35%, and very coarse fraction is over 55%); 2) The coarse soils are sub‐rounded well‐sorted and sub‐stratified to well‐stratified, while the very coarse soils exhibit sub‐rounded to sub‐angular and poorly‐sorted; 3) The accumulations are postulated to have been intermittently deposited in three time periods. This is evidenced by two layers of weathered/residual clay, purple to brick red in color; and 4) It is inferred that the temperature in the study area increased over three time periods, i.e., 280 ka B.P. to 120 ka B.P., 110 ka B.P. to 80 ka B.P. and 70 ka B.P. to 25 ka B.P., and declined twice at 120 ka B.P. and 77 ka B.P. respectively.
Interaction between Downslope and Alongslope Processes on the Margins of Daihai Lake, North China: Implication for Deltaic Sedimentation Models of Lacustrine Rift Basin
Authors: Xinghe YU , Shunli LI , Bintao CHEN , Chengpeng TAN , Jing XIE , Xiaonong HU
Published: August 2012

Daihai Lake, a modern lacustrine rift basin, located in Inner Mongolia, North China, serves as an important modern analog for understanding deltaic depositional processes in an active rift setting. Two of the deltas (Yuanzigou delta and Bulianghe delta) on the margins of Daihai Lake were surveyed to compare and contrast stacking patterns using aerial photographs, field trenching and sediment sampling. Shallow cores and trench data collected from the margins of Daihai Lake indicate that a variety of depositional processes have been active since Daihai Lake formed. Two 3‐D sedimentation models which employ chronostratigraphic correlation technique were generated. The chronostratigraphic sedimentation models predict and represent the architectures and sand‐body continuity of sediments. Stratigraphical coincidence of the broad sheeted drifts and channel erosion suggests a coupling between downslope and alongslope processes. Distributary mouth bars are prevalent in the front of deltas on steeper slopes due to the dominance of down‐slope flows. On the contrary, the along‐slope currents favor the development of distal bar deposits with sheeted sandbodies on gentle depositional slopes. This study provides an insight into the architecture of complex sedimentary facies associated with highlighting key differences between downslope flows and alongslope currents. The distribution of sand within these deltas is of particular interests, with applications in understanding the architecture of hydrocarbon reservoirs formed in lacustrine rift basin.
Paleo‐fires and Atmospheric Oxygen Levels in the Latest Permian: Evidence from Maceral Compositions of Coals in Eastern Yunnan, Southern China
Authors: Longyi SHAO , Hao WANG , Xiaohui YU , Jing LU , Mingquan ZHANG
Published: August 2012

Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo‐fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian‐Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by‐product of paleo‐fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model‐based calculation suggests that the O2 levels near the Wuchiapingian/Changhsingian boundary and the Permian‐Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the Permian‐Triassic boundary crisis.
Identifying the Sources of Solutes in Karst Groundwater in Chongqing, China: a Combined Sulfate and Strontium Isotope Approach
Authors: Junbing PU , Daoxian YUAN , Cheng ZHANG , Heping ZHAO
Published: August 2012

Groundwater from karst subterranean streams is among the world's most important sources of drinking water supplies, and the hydrochemical characteristics of karst water are impacted by both natural environment and people. Therefore, the study of hydrochemistry and its solutes' sources is very important to ensure the normal function of life support systems. In this paper, thirty–five representative karst groundwater samples were collected from different aquifers (limestone and dolomite) and various land use types in Chongqing to trace the sources of solutes and relative hydrochemical processes. Hydrogeochemical types of karst groundwater in Chongqing were mainly of the Ca–HCO3 type or Ca (Mg)–HCO3 type. However, some hydrochemical types of karst groundwater were the K+Na+Ca–SO4 type (G25 site) or Ca–HCO3+SO4 type (G26 and G14 site), indicating that the hydrochemistry of these sites might be strongly influenced by anthropogenic activities or unique geological characteristics. The dissolved Sr concentrations of the studied groundwater ranged from 0.57 to 15.06 μmmol/L, and the 87Sr/86Sr varied from 0.70751 to 0.71627. The δ34S–SO42– fell into a range of –6.8‰–21.5‰, with a mean value of 5.6‰. The variations of both 87Sr/86Sr and Sr values of the groundwater samples indicated that the Sr element was controlled by the weathering of limestone, dolomite and silicate rock. However, the figure of 87Sr/86Sr vs. Sr2+/[K++Na+] showed that the anthropogenic inputs also obviously contributed to the Sr contents. For tracing the detailed anthropogenic effects, we traced the sources of solutes collected karst groundwater samples in Chongqing according to the δ34S value of potential sulfate sources. The variations of both δ34S and 1/SO42– values of the groundwater samples indicated that the atmospheric acid deposition (AAD), dissolution of gypsum (GD), oxidation of sulfide mineral (OS) or anthropogenic inputs (SF: sewage or fertilizer) have contributed to solutes in karst groundwater. The influence of oxidation of sulfide mineral, atmospheric acid deposit and anthropogenic inputs to groundwater in Chongqing karst areas was much widespread.
Changes of Precipitation Infiltration Recharge in the Circumstances of Coal Mining Subsidence in the Shen‐Dong Coal Field, China
Authors: Fawang ZHANG , Yaxin SONG , Hongmei ZHAO , Zhantao HAN , Dong WANG
Published: August 2012

Coal mining subsidence is a universal environmental‐geological problem in mining areas. By selecting the Shen‐Dong coal mining subsidence area as the research field, this paper studies the changes in precipitation infiltration recharge in the circumstances of coal mining subsidence by means of field geological investigation and laboratory simulation experiments, which is expected to provide a scientific basis for eco‐environmental restoration in the mining area. The results indicate that at the unstable stage of subsidence, three types of subsidence in the Shen‐Dong mining area have positive effects on the precipitation infiltration recharge, and the type of full‐thickness bedrock subsidence has the greatest influence. In the stable stage of subsidence, the precipitation infiltration process after long‐term drought and the moisture migration in the aeration zone undergo three different stages: evaporation‐infiltration before precipitation, infiltration‐upward infiltration‐infiltration during precipitation and evaporation‐infiltration after precipitation. During a heavy rainfall infiltration process, the wetting front movement in fine sand, coarse sand and dualistic structure of fine‐coarse sand consists of two stages: the stage of wetting front movement during precipitation, in which the wetting front movement distance has linear relationship with the depth, and the stage of wetting front movement after precipitation, in which the wetting front movement distance has the power function relationship with the depth. The wetting front movement velocity is influenced by the rainfall amount and the lithology in the aeration zone. However, as the depth increases, the movement velocity will decay exponentially.
3‐D Geological Modeling–Concept, Methods and Key Techniques
Authors: Mao PAN , Zhaoliang LI , Zhongbo GAO , Yang YANG , Gengyu WU
Published: August 2012

3‐D geological modeling plays an increasingly important role in Petroleum Geology, Mining Geology and Engineering Geology. The complexity of geological conditions requires different modeling methods in different situations. This paper summarizes the general concept of geological modeling; compares the characteristics of borehole‐based modeling, cross‐section based modeling and multi‐source interactive modeling; analyses key techniques in 3‐D geological modeling; and highlights the main difficulties and directions of future studies.
Dead Sea rhodopsins revisited
Authors: Bodaker Idan , Suzuki Marcelino T. , Oren Aharon , Béjà Oded
Published: August 2012

The Dead Sea is a unique hypersaline ecosystem with near toxic magnesium levels (∼2 M), dominance of divalent cations and a slightly acidic pH. Previously, we reported a haloarchaeon related to Halobacterium salinarum to dominate in a microbial bloom that developed in 1992 in the upper water layers of the lake following massive freshwater runoff. Whether this clade also dominated an earlier bloom in 1980–1982 cannot be ascertained as no samples for cultivation‐independent analysis were preserved. The presence of the light‐driven proton pump bacteriorhodopsin was reported in the 1980–1982 bloom of prokaryotes that had developed in the Dead Sea. To test the hypothesis that bacteriorhodopsin proton pumping may play a major role in determining what type of haloarchaea may dominate in specific bloom conditions, we compared rhodopsin genes recovered from Dead Sea biomass collected in different periods with genes coding for retinal proteins in isolated haloarchaea. Novel bacteriorhodopsin and sensory rhodopsin genes were found in samples collected in 2007 and 2010. The fact that no rhodopsin genes were recovered from samples collected during the 1992 bloom, which was dominated by a single species, suggests that different clades were present in the 1980–1982 and 1992 blooms, and that bacteriorhodopsin proton pumping did not necessarily play a determinative role in the dominance of specific halophiles in the blooms.
Alfaxalone and medetomidine intravenous infusion to maintain anaesthesia in colts undergoing field castration
Authors: Goodwin W. A. , Keates H. L. , Pearson M. , Pasloske K.
Published: August 2012

Reasons for performing the study

The use of alfaxalone and medetomidine administered as an i.v. infusion to maintain anaesthesia has not previously been reported in the horse.

Objectives

To investigate the use of alfaxalone in hydroxpropyl‐beta‐cyclodextrin (Alfaxan) and medetomidine infusion as a field anaesthetic for short‐term surgical procedures in the horse.

Hypothesis

Alfaxalone–medetomidine anaesthesia is suitable for short‐term field anaesthesia in horses.

Methods

Eleven healthy colts underwent 45 min of anaesthesia with an i.v. infusion of alfaxalone (2 mg/kg bwt/h) and medetomidine (5 μg/kg bwt/h) for routine field castration. Horses were premedicated with i.v. acepromazine (0.03 mg/kg bwt), medetomidine (7 μg/kg bwt) and guaiphenesin (35 mg/kg bwt) before i.v. induction with alfaxalone (1 mg/kg bwt). Colts were intubated with an endotracheal tube and 100% oxygen insufflated at 10 l/min. The physiological variables monitored included pulse rate, respiratory rate, direct arterial blood pressure, arterial blood gases and the quality of the inductions and recoveries were scored.

Results

Overall, the anaesthetic period and surgical conditions were acceptable and the quality of the anaesthetic inductions and recoveries was good to excellent. All colts stood on their first attempt (mean ± s.d.) 37 ± 13.5 min after the infusion was stopped. During anaesthesia, cardiopulmonary data, presented as range of mean values at each time point were: heart rate: 45–47 beats/min; mean blood pressure: 104–112 mmHg; respiratory rate: 8 breaths/min; PaO2: 117–172 mmHg; PaCO2: 50–56 mmHg and pH 7.34–7.37.

Conclusions and potential relevance

The co‐administration of alfaxalone and medetomidine as an i.v. infusion after anaesthetic induction with alfaxalone was suitable for short‐term field anaesthesia in the horse.
Deletion of the complement phagocytic receptors CR3 and CR4 does not alter susceptibility to experimental cerebral malaria
Authors: RAMOS T. N. , BULLARD D. C. , BARNUM S. R.
Published: August 2012

Complement receptors for C3‐derived fragments (CR1–4) play critical roles in innate and adaptive immune responses. Of these receptors, CR3 and CR4 are important in binding and phagocytosis of complement‐opsonized pathogens including parasites. The role of CR3 and CR4 in malaria or in cerebral malaria (CM) has received little attention and remains poorly understood in both human disease and rodent models of malaria. CR3 and CR4 are members of the β2‐integrin family of adhesion molecules and are expressed on all leucocytes that participate in the development of CM, most importantly as it relates to parasite phagocytosis (monocytes/macrophages) and antigen processing and presentation (dendritic cells). Thus, it is possible that these receptors might play an important role in disease development. To address this question, we examined the role of CR3−/− and CR4−/− in experimental cerebral malaria (ECM). We found that both CR3−/− and CR4−/− mice were fully susceptible to ECM and developed disease comparable to wild‐type mice. Our results indicate that CR3 and CR4 are not critical to the pathogenesis of ECM despite their role in elimination of complement‐opsonized pathogens. These findings support recent studies indicating the importance of the terminal complement pathway and the membrane attack complex in ECM pathogenesis.
Operation Analysis and Thermoeconomic Evaluation of a Cogeneration Power Plant Operating as a Self-Generator in the Ecuadorian Electrical Market and Sugar Industry
Authors: Bohorquez Washington Orlando Irrazabal , Barbosa João Roberto , Nogueira Luiz Augusto Horta
Published: August 2012

This study evaluates the integral use of the sugarcane bagasse on the productive process of a cogeneration power plant in an Ecuadorian Sugar Company. Thermoelectric power plants burning biomass require a large initial investment and, for example, this initial investment requires $800/kW, which is double the initial investment of a conventional thermoelectric power plant that is $400/kW, and almost similar to the initial cost of a hydroelectric power plant that is $1000/kW. A thermoeconomic study was made on the production of electricity and the sales of the exceeding 27 MW average. From the results, it was concluded that generated electricity costs are $0.0443/kW h, in comparison with the costs of the supplied electricity through fossil power plants with values in the range $0.03–$0.15/kW h and hydroelectric power plants with a value of about $0.02/kW h. Cogeneration power plants burning sugarcane bagasse could contribute to the mitigation of climatic change. This specific case study shows the reduction of the prospective emissions of greenhouse effect gases in the amount of 55,188 ton of CO2 equivalent per year.
Surface tension effects in breaking wave noise
Authors: Deane Grant B.
Published: August 2012

The role of surface active materials in the sea surface microlayer on the production of underwater noise by breaking waves is considered. Wave noise is assumed to be generated by bubbles formed within actively breaking whitecaps, driven into breathing mode oscillation at the moment of their formation by non-equilibrium, surface tension forces. Two significant effects associated with surface tension are identified—a reduction in low frequency noise (<1000 Hz) due to the re-fragmentation of actively radiating bubbles by fluid turbulence within the whitecap and a reduction in overall noise level due to a decrease in the excitation amplitude of bubbles associated with reduced surface tension. The impact of the latter effect on the accuracy of Weather Observations Through Ambient Noise estimates of wind speed is assessed and generally found to be less than ±1  m s−1 for wind speeds less than 10 m s−1 and typical values of surfactant film pressure within sea slicks.
Spatial orientation of different frequencies within the echolocation beam of a Tursiops truncatus and Pseudorca crassidens
Authors: Ibsen Stuart D. , Nachtigall Paul E. , Krause-Nehring Jacqueline , Kloepper Laura , Breese Marlee , Li Songhai , Vlachos Stephanie
Published: August 2012

A two-dimensional array of 16 hydrophones was created to map the spatial distribution of different frequencies within the echolocation beam of a Tursiops truncatus and a Pseudorca crassidens. It was previously shown that both the Tursiops and Pseudorca only paid attention to frequencies between 29 and 42 kHz while echolocating. Both individuals tightly focused the 30 kHz frequency and the spatial location of the focus was consistently pointed toward the target. At 50 kHz the beam was less focused and less precisely pointed at the target. At 100 kHz the focus was often completely lost and was not pointed at the target. This indicates that these individuals actively focused the beam toward the target only in the frequency range they paid attention to. Frequencies outside this range were left unfocused and undirected. This focusing was probably achieved through sensorimotor control of the melon morphology and nasal air sacs. This indicates that both morphologically different species can control the spatial distribution of different frequency ranges within the echolocation beam to create consistent ensonation of desired targets.
Application of modified integration rule to time-domain finite-element acoustic simulation of rooms
Authors: Okuzono Takeshi , Otsuru Toru , Tomiku Reiji , Okamoto Noriko
Published: August 2012

The applicability of the modified integration rule for time-domain finite-element analysis is tested in sound field analysis of rooms involving rectangular elements, distorted elements, and finite impedance boundary conditions. Dispersion error analysis in three dimensions is conducted to evaluate the dispersion error in time-domain finite-element analysis using eight-node hexahedral elements. The results of analysis confirmed that fourth-order accuracy with respect to dispersion error is obtainable using the Fox–Goodwin method (FG) with a modified integration rule, even for rectangular elements. The stability condition in three-dimensional analysis using the modified integration rule is also presented. Numerical experiments demonstrate that FG with a modified integration rule performs much better than FG with the conventional integration rule for problems with rectangular elements, distorted elements, and with finite impedance boundary conditions. Further, as another advantage, numerical results revealed that the use of modified integration rule engenders faster convergence of the iterative solver than a conventional rule for problems with the same degrees of freedom.
Acoustic-gravity waves in atmospheric and oceanic waveguides
Authors: Godin Oleg A.
Published: August 2012

A theory of guided propagation of sound in layered, moving fluids is extended to include acoustic-gravity waves (AGWs) in waveguides with piecewise continuous parameters. The orthogonality of AGW normal modes is established in moving and motionless media. A perturbation theory is developed to quantify the relative significance of the gravity and fluid compressibility as well as sensitivity of the normal modes to variations in sound speed, flow velocity, and density profiles and in boundary conditions. Phase and group speeds of the normal modes are found to have certain universal properties which are valid for waveguides with arbitrary stratification. The Lamb wave is shown to be the only AGW normal mode that can propagate without dispersion in a layered medium.
Inverse estimation of the elastic and anelastic properties of the porous frame of anisotropic open-cell foams
Authors: Cuenca Jacques , Göransson Peter
Published: August 2012

This paper presents a method for simultaneously identifying both the elastic and anelastic properties of the porous frame of anisotropic open-cell foams. The approach is based on an inverse estimation procedure of the complex stiffness matrix of the frame by performing a model fit of a set of transfer functions of a sample of material subjected to compression excitation in vacuo. The material elastic properties are assumed to have orthotropic symmetry and the anelastic properties are described using a fractional-derivative model within the framework of an augmented Hooke’s law. The inverse estimation problem is formulated as a numerical optimization procedure and solved using the globally convergent method of moving asymptotes. To show the feasibility of the approach a numerically generated target material is used here as a benchmark. It is shown that the method provides the full frequency-dependent orthotropic complex stiffness matrix within a reasonable degree of accuracy.
Theoretical and experimental study on active sound transmission control based on single structural mode actuation using point force actuators
Authors: Sanada Akira , Tanaka Nobuo
Published: August 2012

This study deals with the feedforward active control of sound transmission through a simply supported rectangular panel using vibration actuators. The control effect largely depends on the excitation method, including the number and locations of actuators. In order to obtain a large control effect at low frequencies over a wide frequency, an active transmission control method based on single structural mode actuation is proposed. Then, with the goal of examining the feasibility of the proposed method, the (1, 3) mode is selected as the target mode and a modal actuation method in combination with six point force actuators is considered. Assuming that a single input single output feedforward control is used, sound transmission in the case minimizing the transmitted sound power is calculated for some actuation methods. Simulation results showed that the (1, 3) modal actuation is globally effective at reducing the sound transmission by more than 10 dB in the low-frequency range for both normal and oblique incidences. Finally, experimental results also showed that a large reduction could be achieved in the low-frequency range, which proves the validity and feasibility of the proposed method.
Impacts of age on memory for auditory intensity
Authors: Gallun Frederick J. , Diedesch Anna C. , Beasley Robertson
Published: August 2012

It is hypothesized that older listeners are more likely than younger listeners to be impaired when asked to make intensity judgments about target tones embedded in rapidly presented auditory sequences. This study examined this hypothesis by asking listeners ranging in age from 19 to 74 yr to make judgments of intensity based on narrowband noise bursts varying in frequency and intensity. In two experiments, listeners made intensity judgments of target bursts alone or embedded in sequences of bursts. In the first experiment, one of four fixed sequences was presented and had to be identified. In the second experiment, pre- or post-trial bursts acted as cues that identified the frequency of the target burst in the sequence. In both experiments, intensity discrimination thresholds for single bursts were good predictors of performance with sequences and were little affected by age. Significant negative relationships between age and accuracy were observed when single sequences had to be identified or a post-trial cue was used, but no age effects were apparent when a pre-trial cue was used. These data are interpreted as being consistent with previous suggestions that the aging process results in a decline in auditory memory capacity and/or internally generated selective attention.
The least-squares invertible constant-Q spectrogram and its application to phase vocoding
Authors: Ingle A. N. , Sethares W. A.
Published: August 2012

This paper discusses the development of a constant-Q spectrogram representation that is invertible in a least-squares sense. A good quality inverse is possible because this modified transform method, unlike the usual sliding window constant-Q spectrogram, does not discard data samples when performing the variable length discrete Fourier transforms on the signal. The development of a phase vocoder application using this modified technique is also discussed. It is shown that a phase vocoder constructed using the least-squares invertible constant-Q spectrogram (LSICQS) is not a trivial extension of the regular FFT-based phase vocoder algorithm and some of the mathematical subtleties related to phase reassignment are addressed.
The intelligibility of Lombard speech for non-native listeners
Authors: Cooke Martin , Lecumberri Maria Luisa García
Published: August 2012

Speech produced in the presence of noise—Lombard speech—is more intelligible in noise than speech produced in quiet, but the origin of this advantage is poorly understood. Some of the benefit appears to arise from auditory factors such as energetic masking release, but a role for linguistic enhancements similar to those exhibited in clear speech is possible. The current study examined the effect of Lombard speech in noise and in quiet for Spanish learners of English. Non-native listeners showed a substantial benefit of Lombard speech in noise, although not quite as large as that displayed by native listeners tested on the same task in an earlier study [Lu and Cooke (2008), J. Acoust. Soc. Am. 124, 3261–3275]. The difference between the two groups is unlikely to be due to energetic masking. However, Lombard speech was less intelligible in quiet for non-native listeners than normal speech. The relatively small difference in Lombard benefit in noise for native and non-native listeners, along with the absence of Lombard benefit in quiet, suggests that any contribution of linguistic enhancements in the Lombard benefit for natives is small.
The effect of static pressure on the inertial cavitation threshold
Authors: Bader Kenneth B. , Raymond Jason L. , Mobley Joel , Church Charles C. , Felipe Gaitan D.
Published: August 2012

The amplitude of the acoustic pressure required to nucleate a gas or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The magnitude of the inertial cavitation threshold is typically limited by mechanisms other than homogeneous nucleation such that the theoretical maximum is never achieved. However, the onset of inertial cavitation can be suppressed by increasing the static pressure of the fluid. The inertial cavitation threshold was measured in ultrapure water at static pressures up to 30 MPa (300 bars) by exciting a radially symmetric standing wave field in a spherical resonator driven at a resonant frequency of 25.5 kHz. The threshold was found to increase linearly with the static pressure; an exponentially decaying temperature dependence was also found. The nature and properties of the nucleating mechanisms were investigated by comparing the measured thresholds to an independent analysis of the particulate content and available models for nucleation.
Positional targets for lingual consonants defined using electromagnetic articulography
Authors: Yunusova Yana , Rosenthal Jeffrey S. , Rudy Krista , Baljko Melanie , Daskalogiannakis John
Published: August 2012

The study examined the positional targets for lingual consonants defined using a point-parameterized approach with Wave (NDI, Waterloo, ON, Canada). The overall goal was to determine which consonants had unique tongue positions with respect to other consonants. Nineteen talkers repeated vowel-consonant-vowel (VCV) syllables that included consonants /t, d, s, z, ʧ, k, g/ in symmetrical vowel contexts /i, u, a/, embedded in a carrier phrase. Target regions for each consonant, characterized in terms of x,y,z tongue positions at the point of maximum tongue elevation, were extracted. Distances and overlaps were computed between all consonant pairs and compared to the distances and overlaps of their contextual targets. Cognates and postalveolar homorganics were found to share the location of their target regions. On average, alveolar stops showed distinctively different target regions than alveolar fricatives, which in turn showed different target region locations than the postalveolar consonants. Across talker variability in target locations was partially explained by differences in habitual speaking rate and hard palate characteristics.
Use of high-rate envelope speech cues and their perceptually relevant dynamic range for the hearing impaired
Authors: Stone Michael A. , Anton Kristina , Moore Brian C. J.
Published: August 2012

The ability of hearing-impaired (HI) listeners to use high-rate envelope information in a competing-talker situation was assessed. In experiment 1, signals were tone vocoded and the cutoff frequency (fc) of the envelope extraction filter was either 50 Hz (E filter) or 200 Hz (P filter). The channels for which the P or E filter was used were varied. Intelligibility was higher with the P filter regardless of whether it was used for low or high center frequencies. Performance was best when the P filter was used for all channels. Experiment 2 explored the dynamic range over which HI listeners made use of high-rate cues. In each channel of a vocoder, the envelope extracted using fc = 16 Hz was replaced by the envelope extracted using fc = 300 Hz, either at the peaks or valleys, with a parametrically varied “switching threshold.” For a target-to-background ratio of +5 dB, changes in speech intelligibility occurred mainly when the switching threshold was between –8 and +8 dB relative to the channel root-mean-square level. This range is similar in width to, but about 3 dB higher in absolute level than, that found for normal-hearing listeners, despite the reduced dynamic range of the HI listeners.
Ambient noise imaging in warm shallow waters; robust statistical algorithms and range estimation
Authors: Chitre Mandar , Kuselan Subash , Pallayil Venugopalan
Published: August 2012

The high frequency ambient noise in warm shallow waters is dominated by snapping shrimp. The loud snapping noises they produce are impulsive and broadband. As the noise propagates through the water, it interacts with the seabed, sea surface, and submerged objects. An array of acoustic pressure sensors can produce images of the submerged objects using this noise as the source of acoustic “illumination.” This concept is called ambient noise imaging (ANI) and was demonstrated using ADONIS, an ANI camera developed at the Scripps Institution of Oceanography. To overcome some of the limitations of ADONIS, a second generation ANI camera (ROMANIS) was developed at the National University of Singapore. The acoustic time series recordings made by ROMANIS during field experiments in Singapore show that the ambient noise is well modeled by a symmetric α-stable (SαS) distribution. As high-order moments of SαS distributions generally do not converge, ANI algorithms based on low-order moments and fractiles are developed and demonstrated. By localizing nearby snaps and identifying the echoes from an object, the range to the object can be passively estimated. This technique is also demonstrated using the data collected with ROMANIS.
The effect of interaural differences in envelope shape on the perceived location of sounds (L)
Authors: Francart Tom , Lenssen Anneke , Wouters Jan
Published: August 2012

Users of bilateral cochlear implants and a cochlear implant combined with a contralateral hearing aid are sensitive to interaural time differences (ITDs). The way cochlear implant speech processors work and differences between modalities may result in interaural differences in shape of the temporal envelope presented to the binaural system. The effect of interaural differences in envelope shape on ITD sensitivity was investigated with normal-hearing listeners using a 4 kHz pure tone modulated with a periodic envelope with a trapezoid shape in each cycle. In one ear the onset segment of the trapezoid was transformed by a power function. No effect on the just noticeable difference in ITD was found with an interaural difference in envelope shape, but the ITD for a centered percept was significantly different across envelope shape conditions.
Analyses of sex and individual differences in vocalizations of Australasian gannets using a dynamic time warping algorithm
Authors: Krull C. R. , Ranjard L. , Landers T. J. , Ismar S. M. H. , Matthews J. L. , Hauber M. E.
Published: August 2012

The study of the evolution of sexual differences in behavioral and morphological displays requires analyses of the extent of sexual dimorphism across various sensory modalities. In the seabird family Sulidae, boobies show dramatic sexual dimorphism in their vocalizations, and gannet calls have also been suggested to be dimorphic to human observers. This study aimed to evaluate the presence of sexually dimorphic calls in the Australasian gannet (Morus serrator) through the first comprehensive description of its vocalizations recorded at two localities; Cape Kidnappers, where individuals were banded and sexed from DNA samples, and at the Muriwai gannetry, both on the North Island of New Zealand. Calls were first inspected using basic bioacoustic features to establish a library of call element types for general reference. Extensive multivariate tests, based on a dynamic time warping algorithm, subsequently revealed that no sexual differences could be detected in Australasian gannet calls. The analyses, however, indicated extensive and consistent vocal variation between individuals, particularly so in female gannets, which may serve to signal individual identity to conspecifics. This study generates predictions to identify whether differences in Australasian gannet vocalizations play perceptual and functional roles in the breeding and social biology of this long-lived biparental seabird species.