Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whe...Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species （Anolis carol# nensis and Leiocephalus carinatus） primarily use visual signals to communicate with conspecifics and detect potential prey, and two （Aspidoscelis gularis and Scincella lateralis） communicate and forage primarily using chemical signals. Two other species （Hemidactylus turcicus and Sceloporus olivaceus） use both visual and chemical signals. For each species, we performed beha- vioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors （the lat- eral geniculate nucleus and the nucleus rotundus） and one region associated with chemical behaviors （the nucleus sphericus）. With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors .展开更多
The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships am...The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10--12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in the kidneys, and we assessed the fiber type composition of the muscles associated with copulation. In a series of pbylogenetically-informed analyses, we used field behavioral data to determine whether observed rates of copulation were associated with these morphologies.We found that species with larger hemipenes had larger fibers in the RPM （the retractor penis magnus, a muscle that controls hemipenis movement）, and that the evolution of larg- er hemipenes and RPM fibers is associated with the evolution of higher rates of copulatory behavior. However, the sizes of the seminiferous tubules and renal sex segments, and the muscle fiber composition of the RPM, were not associated with copulation rates. Further, body size was not associated with the size of any of the reproductive structures investigated. The results of this study suggest that peripheral morphologies involved in the transfer of ejaculate may be more evolutionarily labile than internal structures involved in ejaculate production.展开更多
In this paper, a semi-parametric regression model with an adaptive LASSO penalty imposed on both the linear and the nonlinear components of the mode is considered. The model is rewritten so that a signed-rank techniqu...In this paper, a semi-parametric regression model with an adaptive LASSO penalty imposed on both the linear and the nonlinear components of the mode is considered. The model is rewritten so that a signed-rank technique can be used for estimation. The nonlinear part consists of a covariate that enters the model nonlinearly via an unknown function that is estimated using Bsplines. The author shows that the resulting estimator is consistent under heavy-tailed distributions and asymptotic normality results are given. Monte Carlo simulations as well as practical applications are studied to assess the validity of the proposed estimation method.展开更多
Microorganisms are ubiquitous in natural environments and in water supply infrastructure including groundwater wells. Sessile-state microorganisms may build up on well surfaces as biofilms and, if excessive, cause bio...Microorganisms are ubiquitous in natural environments and in water supply infrastructure including groundwater wells. Sessile-state microorganisms may build up on well surfaces as biofilms and, if excessive, cause biofouling that reduces well productivity and water quality. Conditions can be improved using biocides and other traditional well rehabilitation measures; however, biofilm regrowth is inevitable given the continuous introduction of microorganisms from the surrounding environment. Alternative and less invasive well maintenance approaches are desirable for reducing biofilm densities while also minimizing harmful disinfection-by- products. The primary objective of this research was to evaluate effectiveness of alternative treatments for inacti- vating microorganisms comprising biofilms. A novel approach was designed for in situ growth of biofilms on steel coupons suspended from ＇chandeliers＇. After more than 100 days of in situ growth, biofilms were harvested, sampled, and baseline biofilm densities quantifed through cultivation. Ultraviolet-C （UV-C） and oxidative treatments including hydrogen peroxide （H2O2）, ozone （O3） and mixed oxidants were then applied to the biofilms in laboratory-scale treatments. Microbial inactivation was assessed by comparing treated versus baseline biofilm densities. H2O2 was the most effective treatment, and decreased density below baseline by as much as 3.1 orders of magnitude. Mixed oxidants were effective for the well having a lower density biofilm, decreasing density below baseline by as much as 1.4 orders of magnitude. Disparity in the response to treatment was apparent in the wells despite their spatial proximity and common aquifer source, which suggests that microbiological communities are more heterogeneous than the natural media from which they originate.展开更多
基金We thank the members of the Johnson Lab at Trinity University for assistance in the field and labor- atory - particularly Bonnie Kircher, Alisa Dill, Michelle Ob- emdorf, Adam Silva, Taren Blackmon, Jordan Bush, McKen- zie Quinn, EUee Cook, Grayam Sailor-Tynes, and Collin Shinkle. We also thank David Ribble, Troy Murphy, Jimmy Roberts, Kevin McIntyre, and three reviewers for comments on an earlier version of this work, and Kevin McIntyre and Kimberly Phillips for statistical advice. This work was funded by a Sigma Xi GIAR （to C.D.R.）, a Trinity University Mind Science Foundation grant （to C.D.R.）, Trinity University＇s HHMI and Biology Summer Undergraduate Research Fel- lowships （to C.D.R.）, Texas Ecolab, and the National Science Foundation （IOS 1257021 to M.A.J.）. All procedures were approved by Trinity University＇s Animal Research Committee （protocol # 050213_MAJ2）.
文摘Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species （Anolis carol# nensis and Leiocephalus carinatus） primarily use visual signals to communicate with conspecifics and detect potential prey, and two （Aspidoscelis gularis and Scincella lateralis） communicate and forage primarily using chemical signals. Two other species （Hemidactylus turcicus and Sceloporus olivaceus） use both visual and chemical signals. For each species, we performed beha- vioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors （the lat- eral geniculate nucleus and the nucleus rotundus） and one region associated with chemical behaviors （the nucleus sphericus）. With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors .
文摘The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10--12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in the kidneys, and we assessed the fiber type composition of the muscles associated with copulation. In a series of pbylogenetically-informed analyses, we used field behavioral data to determine whether observed rates of copulation were associated with these morphologies.We found that species with larger hemipenes had larger fibers in the RPM （the retractor penis magnus, a muscle that controls hemipenis movement）, and that the evolution of larg- er hemipenes and RPM fibers is associated with the evolution of higher rates of copulatory behavior. However, the sizes of the seminiferous tubules and renal sex segments, and the muscle fiber composition of the RPM, were not associated with copulation rates. Further, body size was not associated with the size of any of the reproductive structures investigated. The results of this study suggest that peripheral morphologies involved in the transfer of ejaculate may be more evolutionarily labile than internal structures involved in ejaculate production.
文摘In this paper, a semi-parametric regression model with an adaptive LASSO penalty imposed on both the linear and the nonlinear components of the mode is considered. The model is rewritten so that a signed-rank technique can be used for estimation. The nonlinear part consists of a covariate that enters the model nonlinearly via an unknown function that is estimated using Bsplines. The author shows that the resulting estimator is consistent under heavy-tailed distributions and asymptotic normality results are given. Monte Carlo simulations as well as practical applications are studied to assess the validity of the proposed estimation method.
文摘Microorganisms are ubiquitous in natural environments and in water supply infrastructure including groundwater wells. Sessile-state microorganisms may build up on well surfaces as biofilms and, if excessive, cause biofouling that reduces well productivity and water quality. Conditions can be improved using biocides and other traditional well rehabilitation measures; however, biofilm regrowth is inevitable given the continuous introduction of microorganisms from the surrounding environment. Alternative and less invasive well maintenance approaches are desirable for reducing biofilm densities while also minimizing harmful disinfection-by- products. The primary objective of this research was to evaluate effectiveness of alternative treatments for inacti- vating microorganisms comprising biofilms. A novel approach was designed for in situ growth of biofilms on steel coupons suspended from ＇chandeliers＇. After more than 100 days of in situ growth, biofilms were harvested, sampled, and baseline biofilm densities quantifed through cultivation. Ultraviolet-C （UV-C） and oxidative treatments including hydrogen peroxide （H2O2）, ozone （O3） and mixed oxidants were then applied to the biofilms in laboratory-scale treatments. Microbial inactivation was assessed by comparing treated versus baseline biofilm densities. H2O2 was the most effective treatment, and decreased density below baseline by as much as 3.1 orders of magnitude. Mixed oxidants were effective for the well having a lower density biofilm, decreasing density below baseline by as much as 1.4 orders of magnitude. Disparity in the response to treatment was apparent in the wells despite their spatial proximity and common aquifer source, which suggests that microbiological communities are more heterogeneous than the natural media from which they originate.
