Almost flat bundles and homological invariance of infinite K-area

We extend the notion of an almost flat bundle over a closed Riemannian manifold to bundles over simplicial complexes, and prove that up to a constant factor, this notion is invariant under pullback via maps which induce isomorphisms on fundamental groups. As an application, we show that the property of having infinite K-area only depends on the image of the fundamental class under the classifying map of the universal cover.Comment: 35 page

Value of river discharge data for global-scale hydrological modeling

his paper investigates the value of observed river discharge data for global-scale hydrological modeling of a number of flow characteristics that are required for assessing water resources, flood risk and habitat alteration of aqueous ecosystems. An improved version of WGHM (WaterGAP Global Hydrology Model) was tuned in a way that simulated and observed long-term average river discharges at each station become equal, using either the 724-station dataset (V1) against which former model versions were tuned or a new dataset (V2) of 1235 stations and often longer time series. WGHM is tuned by adjusting one model parameter (γ) that affects runoff generation from land areas, and, where necessary, by applying one or two correction factors, which correct the total runoff in a sub-basin (areal correction factor) or the discharge at the station (station correction factor). The study results are as follows. (1) Comparing V2 to V1, the global land area covered by tuning basins increases by 5%, while the area where the model can be tuned by only adjusting γ increases by 8% (546 vs. 384 stations). However, the area where a station correction factor (and not only an areal correction factor) has to be applied more than doubles (389 vs. 93 basins), which is a strong drawback as use of a station correction factor makes discharge discontinuous at the gauge and inconsistent with runoff in the basin. (2) The value of additional discharge information for representing the spatial distribution of long-term average discharge (and thus renewable water resources) with WGHM is high, particularly for river basins outside of the V1 tuning area and for basins where the average sub-basin area has decreased by at least 50% in V2 as compared to V1. For these basins, simulated long-term average discharge would differ from the observed one by a factor of, on average, 1.8 and 1.3, respectively, if the additional discharge information were not used for tuning. The value tends to be higher in semi-arid and snow-dominated regions where hydrological models are less reliable than in humid areas. The deviation of the other simulated flow characteristics (e.g. low flow, inter-annual variability and seasonality) from the observed values also decreases significantly, but this is mainly due to the better representation of average discharge but not of variability. (3) The optimal sub-basin size for tuning depends on the modeling purpose. On the one hand, small basins between 9000 and 20 000 km2 show a much stronger improvement in model performance due to tuning than the larger basins, which is related to the lower model performance (with and without tuning), with basins over 60 000 km2 performing best. On the other hand, tuning of small basins decreases model consistency, as almost half of them require a station correction factor

Natural Stone Waste Powders Applied to SCC Mix Design

In order to comply with current trends concerning sustainability, saving of primary materials and energy\ud savings, this paper addresses Eco-concrete. The major focus thereby is on the increased efficiency of cement\ud use. Applying a new mix design method for concrete, cement contents can be decreased and partially be substituted\ud by other fine powders, preferentially by waste powders which have no mass application so far. This\ud paper is giving examples of successfully introduced waste powders and characterizes the concretes produced\ud with these powders. These innovative, low cement concrete types obtain medium strength and exhibit furthermore\ud self-compacting abilities. This paper additionally highlights possibilities for the direct use of natural\ud stone sludges or filter cakes. A new grading based design method, developed in the authors’ research\ud group, enables the efficient use of all materials available. The method is applicable to self-compacting concretes,\ud earth-moist concretes and conventionally vibrated concretes

A General Rate Duality of the MIMO Multiple Access Channel and the MIMO Broadcast Channel

We present a general rate duality between the multiple access channel (MAC) and the broadcast channel (BC) which is applicable to systems with and without nonlinear interference cancellation. Different to the state-of-the-art rate duality with interference subtraction from Vishwanath et al., the proposed duality is filter-based instead of covariance-based and exploits the arising unitary degree of freedom to decorrelate every point-to-point link. Therefore, it allows for noncooperative stream-wise decoding which reduces complexity and latency. Moreover, the conversion from one domain to the other does not exhibit any dependencies during its computation making it accessible to a parallel implementation instead of a serial one. We additionally derive a rate duality for systems with multi-antenna terminals when linear filtering without interference (pre-)subtraction is applied and the different streams of a single user are not treated as self-interference. Both dualities are based on a framework already applied to a mean-square-error duality between the MAC and the BC. Thanks to this novel rate duality, any rate-based optimization with linear filtering in the BC can now be handled in the dual MAC where the arising expressions lead to more efficient algorithmic solutions than in the BC due to the alignment of the channel and precoder indices.Comment: Submitted to IEEE Globecom 2008; Fixed dimensions of channel matrix H_k and covariance matrix Z_k, slightly modified conclusio

Simulating river flow velocity on global scale

Flow velocity in rivers has a major impact on residence time of water and thus on high and low water as well as on water quality. For global scale hydrological modeling only very limited information is available for simulating flow velocity. Based on the Manning-Strickler equation, a simple algorithm to model temporally and spatially variable flow velocity was developed with the objective of improving flow routing in the global hydrological model of Water- GAP. An extensive data set of flow velocity measurements in US rivers was used to test and to validate the algorithm before integrating it into WaterGAP. In this test, flow velocity was calculated based on measured discharge and compared to measured velocity. Results show that flow velocity can be modeled satisfactorily at selected river cross sections. It turned out that it is quite sensitive to river roughness, and the results can be optimized by tuning this parameter. After the validation of the approach, the tested flow velocity algorithm has been implemented into the WaterGAP model. A final validation of its effects on the model results is currently performed

Advances and visions in large-scale hydrological modelling : proceedings of the 11th Workshop on Large-scale Hydrological Modelling ; preface

In 1998 the German Universities of Kassel and Giessen organised a workshop on water and solute transport in large drainage basins. The workshop focused on analysing and summarising the state of research, existing problems and perspectives in this research area. It was the second of a series of annual workshops since 1997 that became an important discussion forum for the German-speaking research community in the field of hydrological modelling. Now the 11th Workshop on Large-scale Hydrological Modelling referred to the same questions as posed in 1998 in order to evaluate the developments and advances of the last ten years. Based on keynote presentations, the workshop focused on discussion in working groups where also posters were presented. This volume of "Advances in Geosciences" comprises seven papers referring to the poster contributions. At the end of the volume, an overview paper summarises the outcome of the workshop presentations and discussions (Doll et al.). ..

Improving Adherence to Annual Retinal Screening Among Adult Diabetics in Rural Midwest

Background: Diabetic retinopathy (DR) affects millions of people worldwide and is a main cause of preventable blindness. Experts recommend annual retinal screenings on all diabetic patients. Studies show continuing trends of non-adherence, as well as significant barriers to screenings. Recommendations to overcome barriers and methods to improve adherence among diabetics are topics of interest among healthcare providers. The purpose of this project was to increase annual retinal screening adherence among adult diabetics at a privately owned primary care practice in the rural Midwest. Methods: Staff and 59 patients, chosen through convenience sampling were involved. Pre- and post- implementation surveys were administered to staff to assess knowledge, practice, and attitude regarding DR screening. Education and training were provided to staff to reinforce main concepts of DR and use of office owned tele-retinal imaging technology. Education was posted for patients on the waiting room whiteboard, and educational flyers were provided to patients upon check-in. Staff was encouraged to provide education to each participant upon rooming. Retinal imaging technology was used by staff to complete in- office exams for patients who met inclusion criteria. Uptake of retinal exams was compared to the pre-implementation office adherence retinal exam rate from the prior year. Results: The results were statistically insignificant (p = .248), however there was a proportional increase in patients who received retinal exams during implementation (pre- implementation adherence = 42%, implementation adherence = 48%). Conclusions: Staff reported an increase in knowledge and confidence in usability in pre- existing tele-retinal imaging technology. A small yet clinically significant increase in adherence to retinal exams among diabetics was noted during implementation. Knowledge gained could help to guide future similar interventions

Survey and Service on STD/HIV/AIDS in Namungo Mines,Lindi Region

Namungo is small-scale mining in Ruangwa district, Lindi Region, with deposits of green gemstone (tsavorite). About 400 men and women are living in temporary settlements. In August 2001, an STD/HIV/AIDS workplace intervention started which comprised of: A baseline KAP study with villagers and miners, A survey on infection rates with Syphilis and HIV, Treatment of patients with STD, An educational campaign and Development of plans for continuos collaboration between the mine and the health system. The KAP-study showed that 81% of respondents knew that sexual intercourse/sex without a condom is the main mode of HIV transmission. 80% correctly started that a person infected with HIV can remain a symptomatic for a long period. Half of them responded to had paid sex with more than one partner during the last 12 mouth. Those reporting having used a condom in the past 3 month were 48%. 92% of the respondents reported willingness for Voluntary Counseling and Testing (VCT) to know their HIV status. From 429 people who had came with symptoms of STDs most were treated for discharge syndrome (40% males,24 females) and for genital ulcers (38% in males and females) Testing and counseling for syphilis and HIV was offered to STD clients and volunteers. Infection rates were high in both groups, STD patients and volunteers with 18% for syphilis and 17% for HIV. The highest prevalence with 38% was found in women 30-34 years of age. The high infection rates, risky behavior and a high mobility of the people involved are a challenge to claim holders, health authorities and communities in the vicinity. Regular interventions urgently needed