bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties Analysis of Biological Grafts Used in Pelvic Surgery
Authors: Brătilă Elvira , Brătilă Petre , Comandașu Diana , Cîrstoiu Monica , Bohîlțea Roxana , Boț Mihaela , Mehedințu Claudia
Published: August 2017

Pelvic surgery addresses congenital malformations like Mullerian anomalies, pelvic organ prolapse or after radical intervention, while constructive surgery involves treatment of congenital/iatrogenic absence of organs: uterus or vagina. Intuitively, inert and nondegradable biomaterials appear ideal for this purpose, but surgical reality is that the persistence of a permanent foreign body in the wound has a lot of clinical postoperative disadvantages. This paper aims to discuss the properties of the biologic grafts, detailing the structure of biologic extracellular matrix, the biomechanical properties of biological grafts and the use of extracellular matrix in reconstructive pelvic surgery. A biologic graft used in pelvic surgery is a tridimensional extracellular matrix, acellular and of animal origin. It has as a low risk of transmission of viral and prionic infections and determines reduced inflammatory reaction and a low risk of rejection. The absence of crosslinking facilitates the colonization of the mesh by the host´s cells, thus avoids the foreign body reaction represented by the encapsulation of the mesh by the host. Our experience with clinical use of biological acellular grafts in reconstructive pelvic surgery includes oncoplastic surgery like in cases of vulvar cancer or neovagina reconstruction for Rokintansky syndrome, complications after prolapse surgery treated with polypropylene meshes or relapsing recto-vaginal fistulas. The biomechanical properties evaluated by tensile stress and elastic modulus revealed that biologic grafts with moderate collagen infiltration are the strongest. The degree of cross-linkage influences the rate of degradation and the degree of the inflammatory response triggered by the host organ. Cross-linked collagenous matrices induce little cell infiltration hence there is limited collagen remodeling and graft degradation. On the other hand, in non-cross- linked xenografts cell infiltration is greater with faster degradation rate and collagen production. The decrease in the mechanical strength of the graft materials is related to the lack of collagen infiltration into the material. In conclusion, taking into account the biomechanical properties of biologic grafts, these may be used in reconstructive pelvic surgery and oncoplastic surgery with little complications and good clinical results. They can be attached to large mucosal defects and on potentially septic tissue, they are mechanically resistant and they can be sutured on surrounding healthy tissue.
Simulation of the Upper Limb Recovery Exercises during Physical Therapy Rehabilitation
Authors: Rusu Lucian , Stoia Dan Ioan , Vigaru Cosmina
Published: August 2017

During physical therapy rehabilitation, the required exercises need to be personalized according to the patient motion possibilities. The equipment used to analyzed the patient motion is Zebris CMS-HS. With this equipment, for the studied patient, we are able to record the range of motion, angular velocity and acceleration for each joint during different recovery exercises. This records, are the input data for the upper limb model developed in MatLab Simulink software. Using this application is possible to determined the influence of some external forces that are applied during the studied recovery exercises. In this way is possible to established the direction and the maximum value for the external forces that can be applied. Based on this results, a physiotherapist can adjust the exercises to achieve the best solution for the patient recovery.
Effect of Bi2O3 Content on Properties of Lead Silicate Glass for Microchannel Plate
Authors: Zhang Yang , Wang Yun , Sun Yong , Jia Jin Sheng , Zhang Bing Qiang
Published: August 2017

As a key material for microchannel plate, the lead silicate glasses doped with different content of Bi2O3 was prepared by melt-quenching method. The effect of Bi2O3 content on thermal properties, chemical stability, and resistivity before and after hydrogen reduction of the prepared glasses were studied. The results show that the coefficient of thermal expansion increases with the increasing of Bi2O3 content, while the transition temperature and softening temperature, the acid and alkali resistance, the volume and surface resistivity decrease gradually. Glass with 10% Bi2O3 and without PbO was used to prepare MCP, which has a resistance of 70MΩ and gain of 4,200 at 900V.
Study on Fabrication and Bonding Interface of Explosive Welded Steel/Aluminum/Steel Composite Plate
Authors: Zhou Nan , Jiang Jing , Tang Kui , Tang Song Ze
Published: August 2017

In order to study the explosive welding experimental fabrication technology of multi-layer dissimilar metal plates and the quality of bonding interface, three-layer steel/aluminum/steel composite plates with different thickness distributions were fabricated using the method of explosive welding when their total thicknesses remained same (total 5 mm). Then the stereomicroscope was adopted to investigate the shape of bonding interface and the formed mechanism was also analyzed. In addition, the micro-hardness (Vickers hardness, Hv) distribution of the composite plate in the thickness direction was studied by a low load Vickers hardness tester. The results show that the method of explosive welding can be used to fabricate three-layer steel/aluminum/steel dissimilar metal plates successfully. Meanwhile, wave bonding interface was formed between steel fly plate and aluminum middle plate, straight bonding interface was formed between aluminum middle plate and steel base plate. The maximum Hv value of welded plate appears at the bonding interface with high bonding strength. The bonding strength of both two kinds of welded interface was considered sufficient, which offers experimental support for the explosive welding of multi-layer plates.
Effect of Visible Light Absorber Containing Quinoline Yellow, Azorubine and Green S on Process Control in Microstereolithography
Authors: Bail Robert
Published: August 2017

A visible light absorber containing the colorants Quinoline Yellow, Azorubine and Green S was used as an additive for process control in a microstereolithography process operating under visible light. An aqueous solution containing the three dyestuffs was added in concentrations of 0.1 to 5.0 wt% to a photopolymerizable hydrogel. A series of experiments showed that a minimum concentration of 2.0 wt% of the dye solution and an exposure dose of 100 mJ/cm2 were prerequisites to produce utilizable results on the setup used. Full curing and excellent cure-depth control were only achieved at the highest of the tested concentrations of 5.0 wt% dye solution. The working curve derived for the latter concentration suggested that an exposure dose of 147.6 mJ/cm2 was required to cure an exactly 100-micrometer thin layer. Furthermore, addition of the absorber improved the elasticity of the produced structures from an average modulus of 38.2 MPa at 2% to 30.6 MPa at 5% dye concentration. These results demonstrated that broadband absorbers could be useful as low-cost additives for cure-depth control in photopolymerizable hydrogel materials.
Biodecolorization of Synthetic Dyeing Wastewater by Immobilized Halotolerant Cells
Authors: Namwong Sirilak , Peungsamran Natkamol , Chumee Jitlada
Published: August 2017

The high concentration of salt in textile dye wastewater is one of the limiting factors for evaluating an effective biodecolorization system. Thirty-nine strains of salt-tolerant bacteria were screened for their ability to decolorize azo dyes (cationic blue 41) in the presence of 10% NaCl (w/v). Among them, C15-3 was the most effective strain for decolorizing synthetic dye wastewater. Due to the advantages in the use of immobilized cells over other textile wastewater treatments, the entrapment procedure was selected as it generated preferable conditions for dye decolorization. The ratio suitable for the whole cell entrapment technique was 1% (w/v) alginate and 2.5% (w/v) gelatin. In decolorization batching, the immobilized cells were advantaged over free cells for dye removal over a range of pH and temperatures. Synthetic dye wastewater was decolorized by the immobilized cells in the pH 4.0-10.0 range (pH 4.0-8.0 for whole cell system). The immobilized beads were more effective in the removal of synthetic dye at 50°C (optimal temperature) when compared to free cells (optimally at 40°C). Tests revealed that the decolorization products were less phytotoxic when compared to undecolorized azo dye. Immobilized cells were reusable in 4 cycles at pH 7.2 and 37°C, indicating that the addition of immobilized halotolerant cells may be a suitable treatment for industrial effluents in the breakdown of azo dyes.
Adsorption of Cu(II) onto Cross-Linked Chitosan Coated Bentonite Beads: Kinetic and Isotherm Studies
Authors: Md Ariff Noorul Farhana , Hanafiah Megat Ahmad Kamal Megat , Wan Ngah Wan Saime
Published: August 2017

In this study, cross-linked chitosan coated bentonite (CCB) beads were prepared as a potential adsorbent to adsorb Cu(II) from aqueous solution. As adsorption capacity was affected by several conditions such as initial Cu(II) concentrations, stirring period and temperature, these parameters were important to be investigated. Three different concentrations of Cu(II) were used in the kinetic study, which were 10, 25 and 50 mg/L. The experimental data was found fitted well with the pseudo-second-order model, an indication that chemisorption was the rate controlling mechanism. Isotherm study was done at different temperatures with concentration of Cu(II) was varied from 10 to 200 mg/L. The maximum monolayer adsorption of Cu(II) on CCB beads based on Langmuir isotherm model at 300, 310 and 320 K were 114.94, 119.05 and 77.52 mg/g, respectively. Therefore, adsorption of Cu(II) was preferred at lower temperatures. This work proved CCB beads as an effective adsorbent for fast removal of Cu(II) from wastewater solutions.
Experimental Study on the Performance of Compound Improved HLLS (High Liquid Limit Soil) with Various Curing Agents
Authors: Que Yun , Lin Yi Qian , Gong Fang Ze
Published: August 2017

The HLLS (high liquid limit soil) has the characteristics of high moisture content, low bearing capacity and poor water stability. Most of the existing treatment methods focus on the improvement with a single curing agent, and the research on the improvement of HLLS with various curing agents is still insufficient. This paper presents the characteristics of two kinds of compound improved HLLS based on unconfined compressive strength test. The results show that the unconfined compressive strength of CSIS (Cement / SAP Improved Soil) and CLIS (Cement / Renolith Improved Soil) are greatly improved than those of CIS (Cement Improved Soil) when the curing age is 28d, respectively. The maximum increments of unconfined compressive strength are 0.31MPa and 0.22MPa, respectively. When the cement content is less (more) than 3%, the unconfined compressive strength of CSIS decreases (increases) with the increase of SAP content. When the cement content is constant, the unconfined compressive strength of CLIS increases first and then decreases with the increase of the Renolith content. The optimum mix amount of SAP (Renolith) and cement in CSIS (CLIS) are 0.06% (0.2%) and 5% (3%), respectively. The strength and crack resistance of the two kinds of compound improved soil are better than the one with single curing agent. SAP and Renolith exert the properties of self-curing after water absorption and hydrophobicity, respectively.
Thermal Treatment of Self-Compacting Concrete in Cast-In Situ Construction
Authors: Kharun Makhmud , Nikolenko Yury V. , Stashevskaya Nadezhda A. , Koroteev Dmitry D.
Published: August 2017

Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. Thermal treatment (TT) of SCC can significantly accelerate the strength growth during cast-in-situ construction. This paper presents a technology of TT of structures for cast-in-situ construction with SCC. Application of this technology allows to reduce the turnover of formwork, the labor costs for construction, and the construction period. We also studied the issue of strength development of SCC during TT. For our study, we used SCC of grade C25. Test samples were cured with TT by infrared radiators for 7, 9, 11, 13, 16 and 24 hours. Then warmed samples were tested for compressive strength after 0.5, 4, 12 and 24 hours of cooling period. Study was carried out on the basis of analyzing, generalizing and evaluations of experimental data. A mathematical model is proposed for determining the compressive strength of SCC after one day of curing of SCC with TT.
Characteristics of Alkali-Activated Controlled Low-Strength Material Derived from Red Mud-Slag Blends
Authors: Hwang Chao Lung , Huynh Trong Phuoc
Published: August 2017

This investigation evaluates the characteristics of alkali-activated controlled low-strength materials (CLSM) that were produced using a mixture of red mud (RM) and ground granulated blast-furnace slag (GGBFS) with different RM-to-GGBFS weight ratios (100/0, 90/10, 80/20, and 70/30). A sodium hydroxide (NaOH) solution of 5M concentration was used as an activator. Characteristics of raw materials were checked carefully before using. The effects of GGBFS content on both fresh and hardened properties of the CLSM were evaluated through the tests of flowability, setting time, and compressive strength. Additionally, a scanning electron microscope (SEM) was used to examine the microstructural properties of the CLSM. Experimental results show that using more GGBFS in the mixture reduces flowability and increases the compressive strength of the CLSM. Moreover, the setting time of the fresh CLSM is associated positively with GGBFS content. Further, analysis of the optimal mixture was conducted basing on the test results. Thus, the properties of the CLSM sample containing 80% RM and 20% GGBFS conformed well to the requirements of the Public Works Department, Taipei Government, Taiwan. The results of this study further support the potential use of RM-GGBFS blends for the production of alkali-activated CLSM.
Forgotten, excluded or included? Students with disabilities: A case study at the University of Mauritius
Authors: Pudaruth Sameerchand , Gunputh Rajendra P. , Singh Upasana G.
Published: August 2017

Background: Students with disabilities in the tertiary education sector are more than a just a phenomenon, they are a reality. In general, little attention is devoted to their needs despite the fact that they need more care and attention.Objectives: This paper, through a case study at the University of Mauritius, sought to answer some pertinent questions regarding students with disabilities. Does the University of Mauritius have sufficient facilities to support these students? Are students aware of existing facilities? What additional structures need to be put in place so that students with any form of disability are neither victimised, nor their education undermined? Are there any local laws about students with disabilities in higher education?Method: To answer these questions and others, an online questionnaire was sent to 500 students and the responses were then analysed and discussed. The response rate was 24.4% which showed that students were not reticent to participate in this study.Results: Our survey revealed that most students were not aware of existing facilities and were often neglected in terms of supporting structures and resources. ICT facilities were found to be the best support that is provided at the University of Mauritius. The right legal framework for tertiary education was also missing.Conclusion: Ideally, students with disabilities should have access to special facilities to facilitate their learning experiences at tertiary institutions. Awareness about existing facilities must also be raised in order to offer equal opportunities to them and to enable a seamless inclusion.
Through the eyes of the student: Best practices in clinical facilitation
Authors: Muthathi Immaculate S. , Thurling Catherine H. , Armstrong Susan J.
Published: August 2017

Background: Clinical facilitation is an essential part of the undergraduate nursing curriculum. A number of studies address the issue of clinical facilitation in South Africa, but there remains a lack of knowledge and understanding regarding what students perceive as best practice in clinical facilitation of their learning.Objective: To determine what type of clinical facilitation undergraduate students believe should be offered by clinical facilitators (nurse educators, professional nurses and clinical preceptors) in the clinical area in order to best facilitate their learning.Method: A qualitative, exploratory and descriptive study was conducted. Purposive sampling was performed to select nursing students from the second, third and fourth year of studies from a selected nursing education institution in Johannesburg. The sampling resulted in one focus group for each level of nursing, namely second, third and fourth year nursing students. Interviews were digitally recorded and transcribed verbatim, thematic data analysis was used and trustworthiness was ensured by applying credibility, dependability, confirmability and transferability.Main findings: The data revealed that participants differentiated between best practices in clinical facilitation in the clinical skills laboratory and clinical learning environment. In the clinical skills laboratory, pre-contact preparation, demonstration technique and optimising group learning were identified as best practices. In the clinical learning environment, a need for standardisation of procedures in simulation and practice, the allocation and support for students also emerged.Conclusion: There is a need for all nurses involved in undergraduate nursing education to reflect on how they approach clinical facilitation, in both clinical skills laboratory and clinical learning environment. There is also a need to improve consistency in clinical practices between the nursing education institution and the clinical learning environment so as to support students’ adaptation to clinical practice.
Reported health, lifestyle and clinical manifestations associated with HIV status in people from rural and urban communities in the Free State Province, South Africa
Authors: Pienaar Michélle , Van Rooyen Francois C. , Walsh Corinna M.
Published: August 2017

Background: HIV infection impacts heavily on the infected individual’s overall health status.Aim: To determine significant health, lifestyle (smoking and alcohol use) and independent clinical manifestations associated with HIV status in rural and urban communities.Methods: Adults aged between 25 and 64 years completed a questionnaire in a structured interview with each participant. Blood specimens were analysed in an accredited laboratory using standard techniques and controls. Anthropometric measurements were determined using standardised methods.Results: Of the 567 rural participants, 97 (17.1%) were HIV-infected, and 172 (40.6%) of the 424 urban participants. More than half of HIV-infected rural participants used alcohol and more than 40% smoked. Median body mass index (BMI) of HIV-infected participants was lower than that of uninfected participants. Significantly more HIV-infected participants reported experiencing cough (rural), skin rash (urban), diarrhoea (rural and urban), vomiting (rural), loss of appetite (urban) and involuntary weight loss (rural). Significantly more HIV-uninfected participants reported diabetes mellitus (urban) and high blood pressure (rural and urban). In rural areas, HIV infection was positively associated with losing weight involuntarily (odds ratio 1.86), ever being diagnosed with tuberculosis (TB) (odds ratio 2.50) and being on TB treatment (odds ratio 3.29). In the urban sample, HIV infection was positively associated with having diarrhoea (odds ratio 2.04) and ever being diagnosed with TB (odds ratio 2.49).Conclusion: Involuntary weight loss and diarrhoea were most likely to predict the presence of HIV. In addition, present or past diagnosis of TB increased the odds of being HIV-infected. Information related to diarrhoea, weight loss and TB is easy to obtain from patients and should prompt healthcare workers to screen for HIV.
Sagittal Normal Limits of Lumbosacral Spine in a Large Adult Population: A Quantitative Magnetic Resonance Imaging Analysis
Authors: Pierro Antonio , Cilla Savino , Maselli Giuseppina , Cucci Eleonora , Ciuffreda Matteo , Sallustio Giuseppina
Published: August 2017

Objectives:

The objective of this study was to determine, using magnetic resonance imaging (MRI) of the lumbosacral spine from L1 to S1, the values of the normal sagittal diameter of the spinal canal (SCD), sagittal diameter of the dural sac (DSD), and the normal values of dural sac ratio (DSR) in a large nonsymptomatic adult population and to discriminate whether a vertebral canal is pathological or nonpathological for dural ectasia and/or stenosis.

Materials and Methods:

Six hundred and four patients were prospectively enrolled. All measurements were performed on MRI sagittal T1- and T2-weighted images. The 95% confidence interval (95% CI), defined as mean ± 1.96 standard deviation, was determined for each metric. The upper limit of 95% CI was considered the cutoff value for the normal DSR; the lower limit of 95% CI was considered the cutoff value for the normal SCD.

Results:

SCD cutoff values from L1 to S1 ranged from 14.5–10.1 mm (males) to 15.0–9.9 mm (females). DSD ratios at S1 and L4 level show a significant difference in male and female groups: 11% of S1/L4 values exceeded 1 in male group while only 4% of S1/L4 values exceeded 1 in female group. Mean DSR at each level was significantly higher in female patients than in male patients (P < 0.001), ranging from 0.70 to 0.56 (male) and from 0.82 to 0.63 (female).

Conclusions:

We determined the cutoff values for the normal DSR and for the normal SCD. Our findings show the relevant discrepancies with respect to literature data for diagnosis of lumbar stenosis and/or dural ectasia.
Prevalence of Trypanosoma cruzi and Other Trypanosomatids in Frequently-Hunted Wild Mammals from the Peruvian Amazon
Authors: Morales E. Angelo , Mayor Pedro , Bowler Mark , Aysanoa Esar , Pérez-Velez Erika S. , Pérez Jocelyn , Ventocilla Julio A. , Baldeviano G. Christian , Lescano Andrés G.
Published: August 2017

To better understand the ecology of Trypanosoma cruzi in the northeastern Peruvian Amazon, we evaluated the prevalence of T. cruzi and other trypanosomatids in four orders of wild mammals hunted and consumed by inhabitants of three remote indigenous communities in the Peruvian Amazon. Of 300 wild mammals sampled, 115 (38.3%) were infected with trypanosomatids and 15 (5.0%) with T. cruzi. The prevalence of T. cruzi within each species was as follows: large rodents (Cuniculus paca, 5.5%; Dasyprocta spp., 2.6%), edentates (Dasypus novemcinctus, 4.2%), and carnivores with higher prevalence (Nasua nasua, 18.8%). The high prevalence of T. cruzi and other trypanosomatids in frequently hunted wild mammals suggests a sizeable T. cruzi sylvatic reservoir in remote Amazonian locations.
Global deposition of total reactive nitrogen oxides from 1996 to 2014 constrained with satellite observations of NO2 columns
Authors: Geddes Jeffrey A. , Martin Randall V.
Published: August 2017

Abstract. Reactive nitrogen oxides (NOy) are a major constituent of the nitrogen deposited from the atmosphere, but observational constraints on their deposition are limited by poor or nonexistent measurement coverage in many parts of the world. Here we apply NO2 observations from multiple satellite instruments (GOME, SCIAMACHY, and GOME-2) to constrain the global deposition of NOy over the last 2 decades. We accomplish this by producing top-down estimates of NOx emissions from inverse modeling of satellite NO2 columns over 1996–2014, and including these emissions in the GEOS-Chem chemical transport model to simulate chemistry, transport, and deposition of NOy. Our estimates of long-term mean wet nitrate (NO3−) deposition are highly consistent with available measurements in North America, Europe, and East Asia combined (r =  0.83, normalized mean bias  = −7 %, N =  136). Likewise, our calculated trends in wet NO3− deposition are largely consistent with the measurements, with 129 of the 136 gridded model–data pairs sharing overlapping 95 % confidence intervals. We find that global mean NOy deposition over 1996–2014 is 56.0 Tg N yr−1, with a minimum in 2006 of 50.5 Tg N and a maximum in 2012 of 60.8 Tg N. Regional trends are large, with opposing signs in different parts of the world. Over 1996 to 2014, NOy deposition decreased by up to 60 % in eastern North America, doubled in regions of East Asia, and declined by 20 % in parts of western Europe. About 40 % of the global NOy deposition occurs over oceans, with deposition to the North Atlantic Ocean declining and deposition to the northwestern Pacific Ocean increasing. Using the residual between NOx emissions and NOy deposition over specific land regions, we investigate how NOx export via atmospheric transport has changed over the last 2 decades. Net export from the continental United States decreased substantially, from 2.9 Tg N yr−1 in 1996 to 1.5 Tg N yr−1 in 2014. Export from China more than tripled between 1996 and 2011 (from 1.0 to 3.5 Tg N yr−1), before a striking decline to 2.5 Tg N yr−1 by 2014. We find that declines in NOx export from some western European countries have counteracted increases in emissions from neighboring countries to the east. A sensitivity study indicates that simulated NOy deposition is robust to uncertainties in NH3 emissions with a few exceptions. Our novel long-term study provides timely context on the rapid redistribution of atmospheric nitrogen transport and subsequent deposition to ecosystems around the world.
Multi-generation Chemical Aging of α-Pinene Ozonolysis Products by
Reactions with OH
Authors: Wang Ningxin , Kostenidou Evangelia , Donahue Neil M. , Pandis Spyros N.
Published: August 2017

Abstract. Secondary organic aerosol (SOA) formation from volatile organic compounds (VOCs) in the atmosphere can be thought of as a succession of oxidation steps. The production of later-generation SOA via continued oxidation of the first-generation products is defined as chemical aging. This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. The first-generation α-pinene ozonolysis products were allowed to react further with OH formed via HONO photolysis. After an equivalent of 2–4 days' of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase of the SOA for the experimental conditions used in this work. A more oxygenated product distribution was observed after aging based on the increase in aerosol atomic oxygen to carbon ratio (O : C) by up to 0.04. Experiments performed at intermediate relative humidity (RH) of 50 % showed no significant difference in additional SOA formation during aging compared to those performed at low RH of less than 20 %.
Occurrence rate of dipolarization fronts in the plasma sheet: Cluster observations
Authors: Xiao Sudong , Zhang Tielong , Wang Guoqiang , Volwerk Martin , Ge Yasong , Schmid Daniel , Nakamura Rumi , Baumjohann Wolfgang , Plaschke Ferdinand
Published: August 2017

Abstract. We investigate the occurrence rate of dipolarization fronts (DFs) in the plasma sheet by taking full advantage of all four Cluster satellites (C1–4) from years 2001 to 2009. In total, we select 466 joint-observation DF events, in which 318, 282, 254, and 236 DFs are observed by C1, C2, C3, and C4, respectively. Our findings are as follows: (1) the maximum occurrence rate is ∼ 15.3 events per day at X ∼ 15 RE in the XY plane, and the average occurrence rate is ∼ 5.4 events per day over the whole observation period; (2) the occurrence rate on the dusk side of the plasma sheet is larger and decreases with increasing BXY∕BLobe; (3) the occurrence rate within |Y|  <  6 RE increases gradually from X ≈ −19 to −15 RE and then decreases from X ≈ −15 to −10 RE; (4) the occurrence rate when AE > 200 nT is much larger than that when AE < 200 nT, indicating that DFs preferentially occur during high geomagnetic activity. The magnetic pileup and earthward and duskward ion flows could contribute to the increases in the occurrence rate from X ≈ −19 to −15 RE. We suggest that both geomagnetic activity and multiple DFs contribute to the high occurrence rate of the DFs. In addition, the finite length of the DF in the dawn–dusk direction can affect the chance that a satellite observes the DF.
Alterations in microbial community composition with increasing fCO2: a mesocosm study in the eastern Baltic Sea
Authors: Crawfurd Katharine J. , Alvarez-Fernandez Santiago , Mojica Kristina D. A. , Riebesell Ulf , Brussaard Corina P. D.
Published: August 2017

Abstract. Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( <  20 µm cell diameter) showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.
Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize
Authors: Cai Qian , Zhang Yulong , Sun Zhanxiang , Zheng Jiaming , Bai Wei , Zhang Yue , Liu Yang , Feng Liangshan , Feng Chen , Zhang Zhe , Yang Ning , Evers Jochem B. , Zhang Lizhen
Published: August 2017

Abstract. A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root ∕ shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season) and to mitigate drought risk in dry-land agriculture.
Comparison and validation of eight satellite rainfall products over the rugged topography of Tekeze-Atbara Basin at different spatial and
temporal scales
Authors: Gebremicael Tesfay G. , Mohamed Yasir A. , van der Zaag Pieter , Berhe Amdom G. , Haile Gebremedhin G. , Hagos Eyasu Y. , Hagos Mulubrhan K.
Published: August 2017

Abstract. Satellite rainfall products are considered important options for acquiring rainfall estimates in the absence of ground measurements. However, estimates from these products need to be validated as their accuracy can be affected by geographical position, topography, and climate, as well as by the algorithms used to derive rainfall from satellite measurements. Eight satellite-based rainfall products (TRMM, CHIRPS, RFEv2, ARC2, PERSIANN, GPCP, CMAP and CMORPH) were evaluated against ground observations over the complex topography of the upper Tekeze-Atbara basin in Ethiopia. The performance was evaluated at various temporal (daily, monthly, seasonal) and spatial (point, sub-basin, basin) scales over the period 2002–2015. Results show that CHIRPS, TRMM, and RFEv2 performed well and were able to capture the rainfall measured by rain gauges. The BIAS and correlation of these products were within ±25 % and > 0.5 over different time steps. The remaining products poorly performed at daily time step with higher BIAS (up to ±200 %) and lower correlation (
The critical role of uncertainty in projections of hydrological extremes
Authors: Meresa Hadush K. , Romanowicz Renata J.
Published: August 2017

Abstract. This paper aims to quantify the uncertainty in projections of future hydrological extremes in the Biala Tarnowska River at Koszyce gauging station, south Poland. The approach followed is based on several climate projections obtained from the EURO-CORDEX initiative, raw and bias-corrected realizations of catchment precipitation, and flow simulations derived using multiple hydrological model parameter sets. The projections cover the 21st century. Three sources of uncertainty are considered: one related to climate projection ensemble spread, the second related to the uncertainty in hydrological model parameters and the third related to the error in fitting theoretical distribution models to annual extreme flow series. The uncertainty of projected extreme indices related to hydrological model parameters was conditioned on flow observations from the reference period using the generalized likelihood uncertainty estimation (GLUE) approach, with separate criteria for high- and low-flow extremes. Extreme (low and high) flow quantiles were estimated using the generalized extreme value (GEV) distribution at different return periods and were based on two different lengths of the flow time series. A sensitivity analysis based on the analysis of variance (ANOVA) shows that the uncertainty introduced by the hydrological model parameters can be larger than the climate model variability and the distribution fit uncertainty for the low-flow extremes whilst for the high-flow extremes higher uncertainty is observed from climate models than from hydrological parameter and distribution fit uncertainties. This implies that ignoring one of the three uncertainty sources may cause great risk to future hydrological extreme adaptations and water resource planning and management.
Determination of dissolved nitric oxide in coastal waters of the Yellow Sea off Qingdao
Authors: Liu Chun-Ying , Feng Wei-Hua , Tian Ye , Yang Gui-Peng , Li Pei-Feng , Bange Hermann W.
Published: August 2017

Abstract. We developed a new method for the determination of dissolved nitric oxide (NO) in discrete seawater samples based on the combination of a purge-and-trap setup and a fluorometric detection of NO. 2,3-diaminonaphthalene (DAN) reacts with NO in seawater to form the highly fluorescent 2,3-naphthotriazole (NAT). The fluorescence intensity was linear for NO concentrations in the range from 0.14 to 19 nmol L−1. We determined a detection limit of 0.068 nmol L−1, an average recovery coefficient of 83.8 % (80.2–90.0 %), and a relative standard deviation of ±7.2 %. With our method we determined for the first time the temporal and spatial distributions of NO surface concentrations in coastal waters of the Yellow Sea off Qingdao and in Jiaozhou Bay during a cruise in November 2009. The concentrations of NO varied from below the detection limit to 0.50 nmol L−1 with an average of 0.26 ± 0.14 nmol L−1. NO surface concentrations were generally enhanced significantly during daytime, implying that NO formation processes such as NO2− photolysis are much higher during daytime than chemical NO consumption, which, in turn, lead to a significant decrease in NO concentrations during nighttime. In general, NO surface concentrations and measured NO production rates were higher compared to previously reported measurements. This might be caused by the high NO2− surface concentrations encountered during the cruise. Moreover, additional measurements of NO production rates implied that the occurrence of particles and a temperature increase can enhance NO production rates. With the method introduced here, we have a reliable and comparably easy to use method at hand to measure oceanic NO surface concentrations, which can be used to decipher both its temporal and spatial distributions as well as its biogeochemical pathways in the oceans.
South Atlantic meridional transports from NEMO-based simulations and reanalyses
Authors: Mignac Davi , Ferreira David , Haines Keith
Published: August 2017

Abstract. The South Atlantic meridional transports are evaluated for four state-of-the-art global Ocean Reanalyses (ORAs) and two Free-Running Models (FRMs) in the period 1997–2010. All products employ the Nucleus for European Modelling of the Oceans model, and the ORAs share very similar configurations. The ORA basin interior transports are consistently modified relative to the FRMs, especially in the Argo period, with an improved representation of the south equatorial currents. The ORAs also exhibit systematically higher meridional transports than the FRMs, in closer agreement with large-scale observational estimates at 35° S and western boundary measurements at 11° S. However, the transport impacts by data assimilation still greatly vary between the ORAs, leading to differences up to ~ 8 Sv and 0.4 PW in the South Atlantic Meridional Overturning Circulation and the Meridional Heat Transports (MHTs), respectively. Large inter-product discrepancies arise in the ORA western boundary currents at both upper and deep levels explaining up to ~ 85 % of the inter-product differences in their total MHTs, and meridional velocity differences, rather than temperatures differences, drive ~ 83 % of this spread. Further analysis shows that only very confined temperature differences right against the western boundary geostrophically explain the large boundary current velocity differences. These findings suggest that the current data assimilation schemes, even with Argo data, can consistently constrain the basin interior circulation in the ORAs, but not the overturning transport component dominated by the narrow western boundary currents as in the South Atlantic.
ESTUDO COMPARATIVO ENTRE OS MÉTODOS DE CÁLCULO DE PULMÃO UTILIZANDO A LÓGICA FUZZY E MÉTODO DOS CINQUENTA POR CENTO
Authors: Amaral Tatiana Gondim do , Chen Zhou Guan , E Resende Vitor Hugo Martins , De Sousa Marcos Antônio
Published: August 2017

RESUMO: Levantamentos realizados apontam atrasos em obras gerando insatisfações aos clientes, motivando processos judiciais sobre as construtoras além de custos indiretos adicionais no projeto, levando a prejuízos ao mesmo. Mediante o exposto são necessárias ferramentas mais eficazes para o controle de prazo de obra. Assim, o trabalho visa aplicar e avaliar o método da corrente crítica no planejamento e controle físico de obras, calculando o pulmão do projeto utilizando duas técnicas distintas: Métodos Número Fuzzy trapezoidal (TrFN) e cinquenta por cento. Portanto, realizou-se um estudo de caso de um empreendimento mixed use em Goiânia e um acompanhamento dos serviços estruturais de uma junta, que estão presentes na corrente crítica do projeto. Assim, ao avaliar e comparar os pulmões resultantes, durações calculadas e reais do projeto, se conclui que o Método TrFN é o que mais se aproxima à duração real, pois consulta especialistas; e, mais se integra à equipe, aumentando a aplicabilidade do planejamento, pois os executores do projeto participam na elaboração do mesmo. Já o Método dos Cinquenta por Cento é mais fácil de ser calculado, com a definição mais prática do pulmão resultando um planejamento mais rápido. Baseando-se nesses cálculos, a principal contribuição do trabalho é comparar os resultados de cada técnica quanto à sua agilidade de aplicação, precisão em relação ao real e aplicabilidade em obra.

ABSTRACT: Conducted surveys indicate delays in projects that impact clients, allowing lawsuits over Construction Company and overhead costs of the project, enabling the economic impracticability of it. Through the above are needed more effective tools for term control of the project. Therefore, the work objective is to implement and evaluate the method of the critical chain in the planning and physical control of the project by calculating the project buffer using two different techniques: Trapezoidal Fuzzy Number (TrFN) and Fifty percent Method. Therefore, there was a case study of a mixed use building in Goiânia and monitoring of structural services of a joint, which are present in the project critical chain. Thus, to evaluate and compare the resulting buffer, calculated duration and really happened duration, it is concluded that the TrFN method comes closest to real time as it consults experts; and more integrates the team, increasing the applicability of planning, because the project performers are involved in preparing it. Now the fifty percent method is easier to be calculated with faster definition of the buffer and planning. Based on this calculus, the main contribution of this work is to compare the results of each technique in: application agility, application accuracy, applicability during construction.
AVALIAÇÃO DA CONFIABILIDADE DE PONTES EM CONCRETO PROTENDIDO SOB SOLICITAÇÕES NORMAIS
Authors: Nova Silvia Juliana Sarmiento , Silva Maria Cecilia Amorim Teixeira da
Published: August 2017

RESUMO: O presente trabalho consiste em sistematizar um procedimento para avaliação da confiabilidade estrutural de pontes de concreto protendido, com base no índice de confiabilidade β, e a correspondente probabilidade de falha Pf. O Método de Monte Carlo é utilizado no processo de simulação das variáveis aleatórias, tomadas como sendo as resistências dos materiais, algumas das propriedades geométricas e o carregamento aplicado à estrutura. Como ferramenta para análise estrutural, é utilizado um programa computacional comercial. Os valores obtidos pelo método de simulação são validados através do método analítico FORM, e realiza-se também uma análise de sensibilidade. O procedimento é aplicado a uma ponte de concreto protendido de viga-e-laje. Com base nos resultados alcançados na análise desenvolvida conclui-se que o procedimento sistematizado, o qual utiliza um método de simulação, pode ser utilizado para avaliar a confiabilidade de uma ponte em concreto protendido de uma forma mais prática e efetiva. A análise de sensibilidade permitiu identificar as variáveis que apresentam maior influência na avaliação da segurança da estrutura.ABSTRACT: This paper is proposed to systematize the structural reliability evaluation procedure of prestressed concrete bridges, based on the reliability index β, and the corresponding probability of failure Pf. The Monte Carlo method is used to simulate design variables, taken as the resistances of the materials, some geometrical properties and the loads applied to the structure. As a tool for structural analysis, a commercial computer program is used. The values obtained by simulation method are validated by the analytical method FORM, and a sensitivity analysis is carried out. The procedure is applied to a deck-girder prestressed concrete bridge. Based on the results obtained, it is concluded that the procedure, which is based on a simulation method, can be used to evaluate the reliability of a prestressed concrete bridge in a more practical and effective way. The sensitivity analysis identified the variables with the greatest influence on the assessment of the safety of the structure.
ENSAIOS EM VIGAS DE ALVENARIA SUBMETIDAS À FLEXÃO SIMPLES
Authors: Oliveira Maria das Graças Duarte de , Bacarji Edgar , Guimaraes Gilson Natal
Published: August 2017

RESUMO: Foi realizado um estudo experimental de vigas de alvenaria de concreto submetidas à flexão simples e as variáveis usadas foram a altura da seção transversal e a distribuição das barras da armadura longitudinal. Foram confeccionadas nove vigas com blocos e canaletas de concreto de resistência característica a compressão de 13 MPa. A altura da seção transversal foi definida pela quantidade de fiadas de blocos: uma, duas e três fiadas. As barras de aço da armadura longitudinal foram distribuídas na seção transversal, mantendo constante a taxa de armadura. Foram moldadas três vigas apenas com canaletas e sem estribos, pois seu uso é muito comum na região de Goiânia, GO. Os resultados obtidos foram confrontados com valores encontrados utilizando as recomendações de dimensionamento da norma NBR15961-1 (2011).  De modo geral, as vigas com estribos e com armadura longitudinal distribuídas nas diversas fiadas tiveram desempenho melhor, sendo estas mais dúcteis e mais seguras que as vigas apenas com canaletas e sem estribos. Essas vigas com estribos romperam por flexão e as cargas de ruptura excederam os valores calculados conforme as recomendações de norma. Já as vigas sem estribos romperam por cisalhamento com cargas de ruptura menor ou igual ao recomendado por norma. Este estudo mostra que não devem ser utilizadas vigas de alvenaria sem estribos. ABSTRACT: An experimental study of the flexural behavior of concrete masonry beams subjected to flexure was done and the variables used were the height of the cross section and the distribution of the longitudinal reinforcement along the layers of blocks. Nine concrete masonry beams were cast and tested with concrete blocks of 13 MPa compressive strength. The height of the cross section was defined by the number of blocks: one, two or three layers. The steel longitudinal reinforcement was distributed along the cross section, such that the steel arrangement gave the same steel reinforcing ratio for all beams. Three beams with lintels only and without stirrups were cast since its use if very common in the region of Goiania, GO. Results obtained were compared to those values obtained using recommendations prescribed in Brazilian code of practice NBR 15961-1 (2011). In general, beams with stirrups and with longitudinal reinforcement distributed along the height of the cross section had better performance, were more ductile and safer than beams without stirrups. These beams failed in flexure and ultimate loads were above those calculated using code recommendations. Beams without stirrups had a shear failure with ultimate loads lower than recommended by the code. This study shows that beams without stirrups should not be used.