Stream Stabilization in Western Iowa: Structure Evaluation and Design Manual, HR-385, 1998

Stream degradation is the action of deepening the stream bed and widening the banks due to the increasing velocity of water flow. Degradation is pervasive in channeled streams found within the deep to moderately deep loess regions of the central United States. Of all the streams, however, the most severe and widespread entrenchment occurs in western Iowa streams that are tributaries to the Missouri River. In September 1995 the Iowa Department of Transportation awarded a grant to Golden Hills Resource Conservation and Development, Inc. The purpose of the grant, HR-385 "Stream Stabilization in Western Iowa: Structure Evaluation and Design Manual", was to provide an assessment of the effectiveness and costs of various stabilization structures in controlling erosion on channeled streams. A review of literature, a survey of professionals, field observations and an analysis of the data recorded on fifty-two selected structures led to the conclusions presented in the project's publication, Design Manual, Streambed Degradation and Streambank Widening in Western Iowa. Technical standards and specifications for the design and construction of stream channel stabilization structures are included in the manual. Additional information on non-structural measures, monitoring and evaluation of structures, various permit requirements and further resources are also included. Findings of the research project and use and applications of the Design Manual were presented at two workshops in the Loess Hills region. Participants in these workshops included county engineers, private contractors, state and federal agency personnel, elected officials and others. The Design Manual continues to be available through Golden Hills Resource Conservation and Development.

Stream Stabilization in Western Iowa, HR-352, 1994

Stream channel erosion in the deep loess soils region of western Iowa causes severe damage along hundreds of miles of streams in twenty-two counties. The goal of this project was to develop information, systems, and procedures for use in making resource allocation decisions related to the protection of transportation facilities and farmland from damages caused by stream channel erosion. Section one of this report provides an introduction. Section two presents an assessment of stream channel conditions from aerial and field reconnaissance conducted in 1993 and 1994 and a classification of the streams based on a six stage model of stream channel evolution. A Geographic Information System is discussed that has been developed to store and analyze data on the stream conditions and affected infrastructure and assist in the planning of stabilization measures. Section three presents an evaluation of two methods for predicting the extent of channel degradation. Section four presents an estimate of costs associated with damages from stream channel erosion since the time of channelization until 1992. Damage to highway bridges represent the highest costs associated with channel erosion, followed by railroad bridges and right-of-way; loss of agricultural land represents the third highest cost. An estimate of costs associated with future channel erosion on western Iowa streams is also presented in section four. Section four also presents a procedure to estimate the benefits and costs of implementing stream stabilization measures. The final section of this report, section five, presents information on the development of the organizational structure and administrative procedures which are being used to plan, coordinate, and implement stream stabilization projects and programs in western Iowa.

Hydrocarbon divergence and reproductive isolation in Timema stick insects.

BACKGROUND: Individuals commonly prefer certain trait values over others when choosing their mates. If such preferences diverge between populations, they can generate behavioral reproductive isolation and thereby contribute to speciation. Reproductive isolation in insects often involves chemical communication, and cuticular hydrocarbons, in particular, serve as mate recognition signals in many species. We combined data on female cuticular hydrocarbons, interspecific mating propensity, and phylogenetics to evaluate the role of cuticular hydrocarbons in diversification of Timema walking-sticks. RESULTS: Hydrocarbon profiles differed substantially among the nine analyzed species, as well as between partially reproductively-isolated T. cristinae populations adapted to different host plants. In no-choice trials, mating was more likely between species with similar than divergent hydrocarbon profiles, even after correcting for genetic divergences. The macroevolution of hydrocarbon profiles, along a Timema species phylogeny, fits best with a punctuated model of phenotypic change concentrated around speciation events, consistent with change driven by selection during the evolution of reproductive isolation. CONCLUSION: Altogether, our data indicate that cuticular hydrocarbon profiles vary among Timema species and populations, and that most evolutionary change in hydrocarbon profiles occurs in association with speciation events. Similarities in hydrocarbon profiles between species are correlated with interspecific mating propensities, suggesting a role for cuticular hydrocarbon profiles in mate choice and speciation in the genus Timema.

Liability and Traffic Control Considerations for Low Water Stream Crossings, HR-218, 1981

The current shortage of highway funds precludes the immediate replacement of most of the bridges that have been evaluated as structurally deficient or functionally obsolete or both. A low water stream crossing (LWSC) affords an economical alternative to the replacement of a bridge with another bridge in many instances. However, the potential liability that might be incurred from the use of LWSCs has served as a deterrent to their use. Nor have guidelines for traffic control devices been developed for specific application to LWSCs. This research addressed the problems of liability and traffic control associated with the use of LWSCs. Input to the findings from this research was provided by several persons contacted by telephone plus 189 persons who responded to a questionnaire concerning their experience with LWSCs. It was concluded from this research that a significant potential for accidents and liability claims could result from the use of LWSCs. However, it was also concluded that this liability could be reduced to within acceptable limits if adequate warning of the presence of an LWSC were afforded to road users. The potential for accidents and liability could further be reduced if vehicular passage over an LWSC were precluded during periods when the road was flooded. Under these conditions, it is believed, the potential for liability from the use of an LWSC on an unpaved, rural road would be even less than that resulting from the continuing use of an inadequate bridge. The signs recommended for use in advance of an LWSC include two warning signs and one regulatory sign with legends as follows: FLOOD AREA AHEAD, IMPASSABLE DURING HIGH WATER, DO NOT ENTER WHEN FLOODED. Use of the regulatory sign would require an appropriate resolution by the Board of Supervisors having responsibility for a county road. Other recommendations include the optional use of either a supple mental distance advisory plate or an advisory speed plate, or both, under circumstances where these may be needed. It was also recommended HR-218 Liability & Traffic Control Considerations for Low Water Stream Crossings that LWSCs be used only on unpaved roads and that they not be used in locations where flooding of an LWSC would deprive dwelling places of emergency ground access.

Control Structures for Stabilizing Degrading Stream Channels Pottawattamie County, HR-236, 1987

Stream degradation due to steep stream gradients and large deposits of loess soil is a serious problem in western Iowa. One solution to this problem is to construct grade stabilization structures at critical points along the length of the stream. Iowa Highway Research Board project HR-236, "Pottawattamie County Evaluation of Control Structures for Stabilizing Degrading Stream Channels", was initiated in order to study the effectiveness of such structures in preventing stream degradation. This report describes the construction and 4-year performance of a gabion drop structure constructed along Keg Creek during the winter of 1982-83.

Insights from insects about adaptive social information use.

Copying others can greatly improve individual fitness and is fundamental for the organisation of societies. Yet in some situations it is better to ignore social information and either explore the world individually or use personal information obtained through prior experience. Insects provide excellent models to study the strategic use of social information, but insights from recent research have rarely been viewed in the light of social learning strategies. Here we discuss how insects tailor their reliance on social information to those circumstances for which it is most beneficial, and suggest that insects and vertebrates use similar information-use strategies. We highlight future research avenues, including the use of molecular tools to study the genetic and genomic basis of social information use.

Evaluation of Control Structures for Stabilizing Degrading Stream Channels in Western Iowa, Phases II and III, HR-208A, 1985

Since the turn of the century, tributaries to the Missouri River in western Iowa have entrenched their channels to as much as six times their original depth. This channel degradation is accompanied by widening as the channel side slopes become unstable and landslides occur. The deepening and widening of these streams have endangered about 25% of the highway bridges in 13 counties [Lohnes et al. 1980]. Grade stabilization structures have been recommended as the most effective remedial measure for stream degradation [Brice et al., 1978]. In western Iowa, within the last seven years, reinforced concrete grade stabilization structures have cost between $300,000 and $1,200,000. Recognizing that the high cost of these structures may be prohibitive in many situations, the Iowa Department of Transportation (Iowa DOT) sponsored a study at Iowa State University (ISU) to find low-cost alternative structures. This was Phase I of the stream degradation study. Analytical and laboratory work led to the conclusion that alternative construction materials such as gabions and soil-cement might result in more economical structures [Lohnes et al. 1980]. The ISU study also recommended that six experimental structures be built and their performance evaluated. Phase II involved the design of the demonstration structures, and Phase III included monitoring and evaluating their performance.

Alternate Methods of Stabilizing Degrading Stream Channels in Western Iowa, Phase I, HR-208, 1980

Since the beginning of channel straightening at the turn of the century, the streams of western Iowa have degraded 1.5 to 5 times their original depth. This vertical degradation is often accompanied by increases in channel widths of 2 to 4 times the original widths. The deepening and widening of these streams has jeopardized the structural safety of many bridges by undercutting footings or pile caps, exposing considerable length of piling, and removing soil beneath and adjacent to abutments. Various types of flume and drop structures have been introduced in an effort to partially or totally stabilize these channels, protecting or replacing bridge structures. Although there has always been a need for economical grade stabilization structures to stop stream channel degradation and protect highway bridges and culverts, the problem is especially critical at the present time due to rapidly increasing construction costs and decreasing revenues. Benefits derived from stabilization extend beyond the transportation sector to the agricultural sector, and increased public interest and attention is needed.

Neutral and selection-driven decay of sexual traits in asexual stick insects.

Environmental shifts and lifestyle changes may result in formerly adaptive traits becoming non-functional or maladaptive. The subsequent decay of such traits highlights the importance of natural selection for adaptations, yet its causes have rarely been investigated. To study the fate of formerly adaptive traits after lifestyle changes, we evaluated sexual traits in five independently derived asexual lineages, including traits that are specific to males and therefore not exposed to selection. At least four of the asexual lineages retained the capacity to produce males that display normal courtship behaviours and are able to fertilize eggs of females from related sexual species. The maintenance of male traits may stem from pleiotropy, or from these traits only regressing via drift, which may require millions of years to generate phenotypic effects. By contrast, we found parallel decay of sexual traits in females. Asexual females produced altered airborne and contact signals, had modified sperm storage organs, and lost the ability to fertilize their eggs, impeding reversals to sexual reproduction. Female sexual traits were decayed even in recently derived asexuals, suggesting that trait changes following the evolution of asexuality, when they occur, proceed rapidly and are driven by selective processes rather than drift.

Aplicació del Value Stream Map (VSM) en un sistema de producció de feltres insonoritzants per a l'automòbil

Actualment en el sector industrial, les organitzacions tenen el repte d'optimitzar els seus sistemes productius per a millorar en quant a preu, qualitat i nivell de servei i poder adaptar-se a les exigències dels clients (excel·lència productiva). El present anàlisi, es basa en l'optimització d'una cadena de producció de feltres insonoritzants per a l'automòbil a través de l'eliminació de les pèrdues existents (operacions que no aporten valor afegit al producte final). Per dur-ho a terme, la metodologia emprada és el Value Stream Map (VSM). El VSM és una tècnica desenvolupada sota el model de gestió de la producció Lean Manufacturing, molt visual i entenedora, permet visualitzar i entendre l'estat actual d'un procés. Aquesta, abarca a tota la organització, i te per objectiu recolzar-la en el procés de redisseny dels seus entorns productius per assolir un estat futur millor que possibiliti obtenir resultats en un periode curt de temps. L'objectiu principal de l'estudi, és aplicar l'eina VSM com a mètode per a l'eliminació de les mudes o malbarataments que impedeix la consecució d'una cadena Lean amb el cas concret d'un sistema productiu de feltres insonoritzants. En la primera part del projecte s'introdueix al lector en la teoria del pensament Lean (quins principis té i quins són els objectius) com a marc teòric. Aquí es detalla el procediment, així com les característiques per a la correcta elaboració del VSM actual, per al seu corresponent anàlisi i per a la seva representació del estat futur. En una segona part del projecte, s'exposen les etapes que constitueixen la cadena de producció d'estudi i es duu a terme l'elaboració del Value Stream Map, on es posen de manifest les ineficiències del flux que conformen la línia de producció. Per últim s'analitzen els fluxes, s'identifiquen les pèrdues de la cadena, i a partir d'aquests, es dissenyen i es proposen projectes i accions que permitin establir línies d'actuació per a un millor estat futur. L'estudi ha permés demostrar la validesa del VSM com a eina per a facilitar la consecució i assoliment de millores en la productivitat, competitivitat i rendibilitat dels diferents processos de l'organització en la línia de fabricació de feltres insonoritzats.

The assessment of reproductive success of queens in ants and other social insects

Recently considerable research has focused on the causes of evolution of multiple-queen (polygynous) colonies. In order to better understand the factors which may have led to these polygynous associations it is vital to compare the reproductive success of queens in monogynous (one queen per colony) and polygynous colonies as well as the relative fitness of queens in polygynous colonies. This paper addresses the difficulties arising from such comparisons and their implications with regard to the methods commonly used to assess reproductive success in queens. The relative reproductive success of queens in monogynous and polygynous colonies is commonly assessed by comparing the relative number of reproductives they produce during a single reproductive season. However, shift in queen number seems to be only one aspect of a profound shift in social structure and reproductive strategy that constitutes, in effect, a ''polygyny syndrome''. For example, female reproductives produced in polygynous colonies frequently use a different mode of colony founding, which in turn affects the probability of their survival. Furthermore, queens from monogynous and polygynous colonies frequently differ in their life-span and the number of sexual broods they produce. As a result, the reproductive success of queens in monogynous and polygynous colonies may not be directly related to the relative number of sexuals they produce during a single reproductive season.

Evidence for morphological and adaptive genetic divergence between lake and stream habitats in European minnows (Phoxinus phoxinus, Cyprinidae).

Natural selection drives local adaptation, potentially even at small temporal and spatial scales. As a result, adaptive genetic and phenotypic divergence can occur among populations living in different habitats. We investigated patterns of differentiation between contrasting lake and stream habitats in the cyprinid fish European minnow (Phoxinus phoxinus) at both the morphological and genomic levels using geometric morphometrics and AFLP markers, respectively. We also used a spatial correlative approach to identify AFLP loci associated with environmental variables representing potential selective forces responsible for adaptation to divergent habitats. Our results identified different morphologies between lakes and streams, with lake fish presenting a deeper body and caudal peduncle compared to stream fish. Body shape variation conformed to a priori predictions concerning biomechanics and swimming performance in lakes vs. streams. Moreover, morphological differentiation was found to be associated with several environmental variables, which could impose selection on body and caudal peduncle shape. We found adaptive genetic divergence between these contrasting habitats in the form of 'outlier' loci (2.9%) whose genetic divergence exceeded neutral expectations. We also detected additional loci (6.6%) not associated with habitat type (lake vs. stream), but contributing to genetic divergence between populations. Specific environmental variables related to trophic dynamics, landscape topography and geography were associated with several neutral and outlier loci. These results provide new insights into the morphological divergence and genetic basis of adaptation to differentiated habitats.

Resistance of stored-product insects to phosphine

The objectives of this work were to assess phosphine resistance in insect populations (Tribolium castaneum, Rhyzopertha dominica, Sitophilus zeamais and Oryzaephilus surinamensis) from different regions of Brazil and to verify if the prevailing mechanism of phosphine resistance in these populations involves reduced respiration rates. Sixteen populations of T. castaneum, 15 of R. dominica, 27 of S. zeamais and eight of O. surinamensis were collected from 36 locations over seven Brazilian states. Each population was tested for resistance to phosphine, based on the response of adults to discriminating concentrations, according to FAO standard method. For each insect species, the production of carbon dioxide of the most resistant and of the most susceptible populations was inversely related to their phosphine resistance. The screening tests identified possible phosphine resistant populations. R. dominica and O. surinamensis were less susceptible to phosphine than the other two species. The populations with lower respiration rate showed a lower mortality at discriminating concentration, possibly related to a phosphine resistance mechanism. Phosphine resistance occurs in stored-product insects, in different regions of Brazil, and the resistance mechanism involves reduced respiration rate.

Stream Water Quality Summary, 2013

Summary of stream water quality collected in 2013.

Stream Water Quality Summary, 2000-2013

Summary of stream water quality data collected from 2000 through 2013.