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.

Genetic evidence for female-biased dispersal and gene flow in a polygynous primate.

Many models of sex-biased dispersal predict that the direction of sex-bias depends upon a species' mating system. In agreement with this, almost all polygynous mammals show male-biased dispersal whereas largely monogamous birds show female-biased dispersal (FBD). The hamadryas baboon (Papio hamadryas hamadryas) is polygynous and so dispersal is predicted to be male biased, as is found in all other baboon subspecies, but there are conflicting field data showing both female and male dispersal. Using 19 autosomal genetic markers genotyped in baboons from four Saudi Arabian populations, we found strong evidence for FBD in post-dispersal adults but not, as expected, in pre-dispersal infants and young juveniles, when we compared male and female: population structure (F(st)), inbreeding (F(is)), relatedness (r), and the mean assignment index (mAIc). Furthermore, we found evidence for female-biased gene flow as population genetic structure (F(st)), was about four times higher for the paternally inherited Y, than for either autosomal markers or for maternally inherited mtDNA. These results contradict the direction of sex-bias predicted by the mating system and show that FBD has evolved recently from an ancestral state of male-biased dispersal. We suggest that the cost-benefit balance of dispersal to males and females is tightly linked to the unique hierarchical social structure of hamadryas baboons and that dispersal and social organization have coevolved.

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.

"Suddenly I get into the zone": Examining discontinuities and nonlinear changes in flow experiences at work

Work-related flow is defined as a sudden and enjoyable merging of action and awareness that represents a peak experience in the daily lives of workers. Employees" perceptions of challenge and skill and their subjective experiences in terms of enjoyment, interest and absorption were measured using the experience sampling method, yielding a total of 6981 observations from a sample of 60 employees. Linear and nonlinear approaches were applied in order to model both continuous and sudden changes. According to the R2, AICc and BIC indexes, the nonlinear dynamical systems model (i.e. cusp catastrophe model) fit the data better than the linear and logistic regression models. Likewise, the cusp catastrophe model appears to be especially powerful for modelling those cases of high levels of flow. Overall, flow represents a nonequilibrium condition that combines continuous and abrupt changes across time. Research and intervention efforts concerned with this process should focus on the variable of challenge, which, according to our study, appears to play a key role in the abrupt changes observed in work-related flow.

Dynamics of flow: a nonlinear perspective

The aims of this study are to consider the experience of flow from a nonlinear dynamics perspective. The processes and temporal nature of intrinsic motivation and flow, would suggest that flow experiences fluctuate over time in a dynamical fashion. Thus it can be argued that the potential for chaos is strong. The sample was composed of 20 employees (both full and part time) recruited from a number of different organizations and work backgrounds. The Experience Sampling Method (ESM) was used for data collection. Once obtained the temporal series, they were subjected to various analyses proper to the com- plexity theory (Visual Recurrence Analysis and Surrogate Data Analysis). Results showed that in 80% of the cases, flow presented a chaotic dynamic, in that, flow experiences delineated a complex dynamic whose patterns of change were not easy to predict. Implications of the study, its limitations and future research are discussed.

Balanç hidroquímic d'una conca mediterrània en estat seminatural: el cas de la riera d'Arbúcies

A study of hydrochemical characteristics of the Arbúcies river (a seminatural mediterranean basin) has been undertaken during 1991. Mean solute yield for each ion has been determined using the correlation curves between discharge and concentration, and the flow duration curve. The hydrochemical budget of the Arbúcies drainage basin shows that the basin is a net source for al1 the elements. The cationic denudation rate obtained in this granitic basin is 5.24 keqhalyear. This high rate is due to the intensive chemical weathering of the granodionte, that delivers an important amount of cations which will release to be transported. The results demostrate clearly the strength of lithological control on stream loads, particulary on the dissolved component.

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.

LiveCount Assay: concomitant measurement of cytolytic activity and phenotypic characterisation of CD8(+) T-cells by flow cytometry.

Tumour immunologists strive to develop efficient tumour vaccination and adoptive transfer therapies that enlarge the pool of tumour-specific and -reactive effector T-cells in vivo. To assess the efficiency of the various strategies, ex vivo assays are needed for the longitudinal monitoring of the patient's specific immune responses providing both quantitative and qualitative data. In particular, since tumour cell cytolysis is the end goal of tumour immunotherapy, routine immune monitoring protocols need to include a read-out for the cytolytic efficiency of Ag-specific cells. We propose to combine current immune monitoring techniques in a highly sensitive and reproducible multi-parametric flow cytometry based cytotoxicity assay that has been optimised to require low numbers of Ag-specific T-cells. The possibility of re-analysing those T-cells that have undergone lytic activity is illustrated by the concomitant detection of CD107a upregulation on the surface of degranulated T-cells. To date, the LiveCount Assay provides the only possibility of assessing the ex vivo cytolytic activity of low-frequency Ag-specific cytotoxic T-lymphocytes from patient material.

Concentration and estimated flow of soluble non-ammonia nitrogen entering the omasum of dairy cows as influenced by different protein supplements

Selostus: Valkuaistäydennyksen vaikutus lypsylehmän pötsistä virtaavan liukoisen rehuperäisen typen pitoisuuteen ja määrään sisärehuruokinnalla

Flow cytometry in the analysis of cellular populations

Flow cytometry has become a valuable tool in cell biology. By analyzing large number of cells individually using light-scatter and fluorescence measurements, this technique reveals both cellular characteristics and the levels of cellular components. Flow cytometry has been developed to rapidly enumerate cells and to distinguish among different cell stages and structures using multiple staining. In addition to high-speed multiparametric data acquisition, analysis and cell sorting, which allow other characteristics of individual cells to be studied, have increased the interest of researchers in this technique. This chapter gives an overview of the principles of flow cytometry and examples of the application ofthe technique.

Adjustable Suture Removal: Increasing Aqueous Flow in "Safe" Trabeculectomy.

Purpose: Aqueous flow through trabeculectomy blebs has been suggested to influence filtration bleb survival. We investigated the relationship between the requirement to increase aqueous flow via adjustable suture removal and surgical outcomes following "safe trabeculectomy" with mitomycin C (MMC). Methods: 62 consecutive eyes of 53 patients underwent fornix based trabeculectomy with adjustable sutures, intraoperative MMC and intensive postoperative steroids. Subconjunctival antimetabolite injections and bleb needlings were administered according to bleb vascularity and IOP trends. Main outcome measures were: success rates (definition: IOP≤21mmHg and 20% IOP reduction); number of antimetabolite injections; bleb needlings; number of of eyes recommencing glaucoma medications and complications. Results: Mean age was 70.4±16.0 years (mean± SD); mean preoperative IOP was 24.5±9.1 mmHg and decreased to 12.3±8.9mmHg postoperatively. Mean number of sutures was 2.6 ± 0.7. Eyes were divided into 2 groups in relation to the number of sutures removed. The number of subconjunctival MMC injections required for those requiring 2 suture removals was significantly greater than those requiring 1 suture removal (p<0.05) The number of needlings and 5FU injections also increased but did not reach significance (p=0.09 and p=0.34 respectively). Least-squared linear regression analysis showed the number of needlings required had a statistically significant (p=0.05) trend with respect to time elapsed between surgery and first suture removal. No other interventions had significant trends. Mean time between surgery and suture removal was: 4.2±9.2 weeks (suture #1) and 5.7±9.7 weeks (suture#2). Antiglaucoma medication was restarted in only 5 eyes. Postoperative complications were infrequent: Seidel (3.2%), peripheral choroidal effusions at any time (3.2%), and shallow anterior chamber (1.6%). Conclusion: Eyes requiring a greater number of suture removals required a significantly greater number of antifibrosis interventions. The time elapsed before suture removal was inversely related to the number of postoperative needlings, suggesting these eyes may have decreased aqueous production and therefore require aggressive post-operative management to prevent bleb failure.

Lower limb high arterial flow induced by tenofovir and emtricitabine treatment.

Here, we describe a case of an HIV-infected patient with right lower limb oedema that appeared after initiation of tenofovir and emtricitabine treatment. The patient was fully investigated by serial heart and vessel echo-Doppler examination. Oedema of the lower limb was attributed to a transient drug-induced fivefold increase in peripheral artery flow, which was induced by a reduction in peripheral arterial resistance. The possible mechanisms of disease are discussed.

Redistribution of gastric blood flow by embolization of gastric arteries before esophagectomy.

Background. Anastomotic leak remains a common and potentially deleterious complication after esophagectomy. Preoperative embolization of the left gastric artery and splenic artery (PAE) has been suggested to lower anastomotic leak rates. We present the results of our 5-year experience with this technique.Methods. All patients undergoing PAE before esophagectomy since introduction of this technique in 2004 were compared in a 1: 2 matched-pair analysis with patients without PAE. Matching criteria were type of anastomosis, neoadjuvant treatment, comorbidity, and age. Data were derived from a retrospective chart review from 2000 to 2006 that was perpetuated as a prospective database up to date. Outcome measures were anastomotic leak, overall complications, and hospital stay.Results. Between 2000 and 2009, 102 patients underwent esophagectomy for cancer in our institution with an overall leak rate of 19% and a mortality of 8%. All 19 patients having PAE since 2004 were successfully matched 1: 2 to 38 control patients without PAE; both groups were similar regarding demographics and operation characteristics. Two PAE (11%) and 8 control patients (21%) had an anastomotic leak, but the difference was statistically not significant (p = 0.469). Overall and major complication rates for PAE and control group were 89% versus 79% (p = 0.469) and 37% versus 34% (p = 1.000), respectively. Median intensive care unit and hospital stay were 3 versus 3 days (p = 1.000) and 22 versus 17 days (p = 0.321), respectively.Conclusions. In our experience, PAE has no significant impact on complications and anastomotic leak in particular after esophagectomy. (Ann Thorac Surg 2011;91:1556-61) (C) 2011 by The Society of Thoracic Surgeons