bluuebunny/crossref_metadata_2025 huggingface dataset:
Annealing Effect on the Surface Morphology and Photoluminescence Properties of ZnO Hexagonal Rods by Immersion Method
Authors: Azlinda Ab Aziz , Khusaimi Zuraida , Fadzilah Suhaimi Mohd Husairi , Nasruddin Nor Iyazi , Abdullah S. , Rusop Mohamad
Published: October 2012

ZnO hexagonal rod structure were prepared by immersion method deposited onto Si (Si/ZnO) and gold-seeded Si substrate (ZnO/Au/Si). The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscopy. The shape of ZnO showed growth of rods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that diameter size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.
Modeling and Optimization of Critical Depth in High Speed End Milling of Soda Lime Glass
Authors: Mahmud M.A. , Amin A.K.M. Nurul , Arif M.D.
Published: October 2012

One of the most hard and brittle material is glass. Due to the properties of low fracture toughness it is very difficult to being machined having good surface quality. Hence it is required to be machined in such a way that brittle fracture does not appear in the new machined surface, which is only possible in ductile mode machining or the removal of material in the plastic state. Above all machining of glass is the most challenging in current state of mechanical machining. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered. This paper presents the mathematical model and optimization results of an experimental study of high speed end milling by the consideration of amplitude time display (Time Domain), FFT Diagram (Frequency Domain) and surface characteristics to find out the maximum critical depth for higher material removal which is crack free surface having good surface finishes. Mathematical model of the response parameter, the critical depth is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The optimization was carried out by the optimization features of Design Expert software.
Thermogravimetric Analysis of OMMT Filled HDPE/EPDM Treated EB Irradiation
Authors: Jamal N.A. , Anuar Hazleen , Hassan Noor Azlina , Abdul Razak Shamsul Bahri
Published: October 2012

In the current study, high density polyethylene (HDPE)/ ethylene propylene diene monomer (EPDM) blend and organophilic montmorillonite (OMMT) filled HDPE/EPDM was develop aiming at enhancing the thermal properties. Maleic anhydride polyethylene (MAPE) agent and electron beam (EB) irradiation technique were applied as HDPE/EPDM blend and OMMT filled HDPE/EPDM treatments. HDPE/EPDM blend and OMMT filled HDPE/EPDM were first prepared via melt intercalation technique at 4 vol% OMMT loading. For EB irradiation technique, the absorbed dose was set at 100 kGy. The effectiveness of these surface modification treatments were compared with control one (no surface modification) and analyzed based on the thermal test as well as transmission electron microscope (TEM). It was found that the thermal properties of both HDPE/EPDM blend and OMMT filled HDPE/EPDM were significantly enhanced by EB irradiation technique as compared to the control and MAPE systems. Transmission electron microscope (TEM) illustrated the mixed intercalated and partial exfoliated structures of OMMT filled HDPE/EPDM with EB irradiation technique.
Aluminum-Silicon Carbide Composites for Enhanced Physio-Mechanical Properties
Authors: Sujan D. , Yeo C.W. , Rahman Muhammad Ekhlasur , Reddy M. Mohan , Maleque Md Abdul , Mohammad Yeakub Ali
Published: October 2012

Stir casting method is used in the production of SiC reinforced-aluminium metal matrix composite (AMMC) to enhance the properties of base metal. Different weight fraction of Silicon carbide, SiC (5 wt%, 10 wt% and 15 wt %) particulate-reinforced AMMCs are fabricated and characterizations of physical and mechanical properties of the materials are performed based on the experimental. The microstructure of the fabricated composite material are studied and analyzed. The results indicate that the mechanical properties of the composite, including yield strength, tensile strength and hardness are enhanced by the increment of the weight fraction of reinforcing phase. Nevertheless, the elongation and fracture toughness of the composite decreased as the reinforcing phase increased. This is mainly due to the brittleness of the SiC particles which act as micro void initiator.
Corrosion Behavior of Fe-Mn-C Alloy as Degradable Materials Candidate Fabricated via Powder Metallurgy Process
Authors: Harjanto Sri , Pratesa Yudha , Suharno Bambang , Syarif Junaidi
Published: October 2012

Fe-Mn alloys are prospective degradable materials for coronary stents. Several methods and strategies are investigated to produce excellence properties for this application, such as addition of alloying elements. The study is focused on the corrosion behavior of novel Fe-Mn alloys, i.e. Fe-25Mn-1C and Fe-35Mn-1C fabricated by powder metallurgy process. Addition of carbon is intended to obtain the phase that has ability to easily degradable without compromising its mechanical properties. The results show that austenite phase formed from this process and corrosion rate increased in proportion with the manganese addition from 32.2 mpy (Fe-25Mn-1C) to 43.7 mpy (Fe-35Mn-1C) using polarization methods. The presence of porosity, which cannot be extinguished by sintering, makes the degradation favorable. The results of this study indicate that these alloys have prospective properties to be applied as degradable biomaterials.
Effect of TiO2 Nanofiller on Nanocomposited PMMA/TiO2 Thin Film
Authors: Hafizah N.N. , Lyly Nyl Ismail , Musa M.Z. , Rusop Mahmood Mohamad
Published: October 2012

In this study, PMMA/TiO2 nanocomposite thin films were prepared by using sonication spin coating technique. The PMMA and TiO2 solution were mixed together and sonicated for 1h to confirm the homogeneity of the sample. The thin films obtained were then measured using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR). FESEM micrograph reveals that the uniformity increases with the increase of TiO2 weight percentage.
Morphology and Water Absorption Analysis on Single Fibre and Leaf of Typha latifolia
Authors: Othman Maizatulnisa , Ruzaidi G. , Khalisanni K. , Nazarudin Z.
Published: October 2012

The aim of this study is to determine the morphology and water uptake behaviour of single fibre and leaf of Typha Latifolia. In order to study the morphology and water uptake properties of the fibre, a single fibre was taken out from the Typha Latifolia leaf. The leaf was divided into two-part that are top and bottom parts. From direct observation towards leaves, the leaf at the bottom part has more cavities compare to the leaf on the top parts of the tree. Based to morphology analysis, the fibres were found randomly held in the middle of the top part and there were spongy structures in the middle of the bottom part of the leaves. SEM analysis evidenced that a single Typha Latifolia fibre is from a bulk of fibre. A water absorption result at top part of the leaf is higher than bottom part of the leaf with 79.79% and 66.63%, respectively. It was observed that different part of Typha latifolia could absorb water with different percentages.
Application of Focused Ion Beam Micromachining: A Review
Authors: Atiqah N. , Jaafar I.H. , Mohammad Yeakub Ali , Asfana B.
Published: October 2012

Fabrication of micro and nanoscale components are in high demand for various applications in diversified fields that include automotive, electronics, communication and medicine. Focused ion beam (FIB) machining is one of the techniques for microfabrication of micro devices. This paper presents a review of FIB machining technology that include its parameter, responses, its important component systems, as well as the fundamentals of imaging, milling (etching) and deposition techniques. The application of FIB in micromachining is also presented.
Effect of Deposition Voltage on Microstructure and Optical Properties of TiO2 Thin Film via Electrophoretic Deposition
Authors: Ghannadi Saber , Abdizadeh H. , Golobostanfard M.
Published: October 2012

In this study nanocrystalline anatase TiO2 thin films were prepared by electrophoretic deposition of titania sol at various applied voltages. The well-known sol-gel method was used to prepare the titania sol. The influence of applied voltage on the structure, morphology and optical properties of thin films has been characterized by X-ray diffraction, field emission scanning electron microscopy and UV-Vis spectroscopy. The results show that the thickness of the films formed on the substrate increases with increasing the applied voltage. However, with increasing the thickness of the films, the cracks increased and the transparency reduced in the visible region.
Structural, Optical and Electrical Characterization of Mo Doped In2O3 Thin Films Prepared via Sol-Gel Spin Coating Technique
Authors: Mohammadi Saeed , Abdizadeh Hossein , Golobostanfard Mohammad Reza
Published: October 2012

The optically transparent conducting molybdenum doped indium oxide (IMO) thin films were deposited on glass substrates by sol-gel spin coating technique. The effect of various molybdenum contents in the range of 0.25–1 at.% on the structural, morphological, optical and electrical properties was studied. XRD results confirmed the formation of cubic bixbyite structure of In2O3 with preferred orientation along (222) plane. Microstructural studies show nearly spherical morphology for thin films with size in the range of 20-40 nm. The films doped with 0.25 at.% Mo found to exhibit a minimum electrical resistivity of 188×10-3 Ω.cm and an average optical transmittance of more than 80% in the visible region with a band gap of 3.85 eV.
Initial Stage Oxidation of Cr in Dry and Wet Environment at 1073 K and the Significant Differences of FT – IR Spectra Produced Thereof
Authors: Kaderi Akbar , Meskon Shahrul Razi , Ani Mohd Hanafi , Othman Raihan
Published: October 2012

Little information has been known on the initial – stage oxidation if there is water vapor involved. Cr samples of 10 mm × 10 mm × 1 mm were isothermally oxidized in dry and wet environment respectively for 86.4 ks. Compact and even surface of Cr2O3 was formed on samples oxidized in dry environment. However, the ability to form compact and even Cr2O3 was retarded in wet environment. XRD analysis on all samples shows that Cr2O3 can be formed in dry and wet environment. The IR transmission spectra for samples oxidized in dry environment, were consisting of more intense peak while samples oxidized in wet environment has more relaxed peak. Moreover the peak of samples oxidized in dry tends to be narrower, while samples oxidized in wet tend to have broader peak.
TiO2/Solid State Polymer Junction for Photovoltaic Application
Authors: Alaei Iraj , Al-Bat’hi Souad A.M.
Published: October 2012

Solid state polymer electrolyte blend of polyethylene oxide, chitosan, ammonium iodide, and iodine crystals has been prepared by solution cast technique. The highest ionic conductivity of the polymer electrolyte was 1.18 × 10−5 S cm−1 at room temperature. Addition of chitosan to the electrolyte has improved its mechanical properties. A photovoltaic junction with configuration ITO/TiO2-solid state polymer blend electrolyte/ITO has been constructed. The open circuit voltage Voc, short circuit current density Jsc, and fill factor FF% obtained from the photovoltaic system under white light illumination of 100W Tungsten lamp are 320-350 mV, 0.59-2.5μAcm-2 and 42%-59% respectively.
Experimental and Numerical Simulation of Hollow Structure under Compression Loading
Authors: Abdullah Kassim A. , Mohamed Ali Jaffar S. , Aminanda Yulfian
Published: October 2012

Buckling and crushing behaviour of hollow structure was studied through experiments and numerical simulation. The experimental material was a thin aluminium square tube (38 x 38, 1.2 mm thick). Quasi-static crushing load was applied using a Universal Testing Machine, Shimadzu Autograph (AG-X) series which uses TRAPEZIUMX software for control and data logging. Finite element simulation of the crushing test was done using LS-DYNA software. Results of the two analyses were compared and found in good agreement. The study provides an insight on ways to increasing energy absorption of light weight aluminium tubes. The simulation procedure can be used for further investigation of aluminium tubes of different cross section areas and geometries.
Eco-Friendly Machining of T6061 Aluminium Alloy Using Titanium Carbonitride (TiCN) Coated Tools
Authors: Ariff Tasnim Firdaus , Sabiyah Mohamad Yazid , Adam Mohd Amirul , Nor Mohd Anuar
Published: October 2012

Traditional wet machining methods using oil based cutting fluids and water based cutting fluids are currently being used widely in the industry. Since oil based cutting fluids contributes to environmental problems, water based cutting fluids were introduced to minimize these effects even though not extensively used everywhere in all parts of the world. Eco-friendly machining is introduced for making the environment a better and healthier place by reducing the amount of contaminants and pollution into the water system. Two biodegradable cutting fluids have been chosen in this study; vegetable oil (palm oil) and water based cutting fluids. The wear behavior of TiCN coated tools is studied for three different cutting speeds (333, 415 and 517 m/min) and at two different cutting parameters; depth-of-cut, d and feed rate, f (d = 0.2 mm, f = 0.4 mm/rev and d = 0.4 mm, f = 0.6 mm/rev). Wear rate for machining using palm oil cutting fluid is lower (longer tool life) than the wear rate obtained from using water based coolants. Palm oil has better lubrication properties compared to water based coolants which have better cooling effects. The optimum cutting parameters for machining T6061 Aluminium alloy using TiCN coated tool is found; 333 m/min (water based) and 415 m/min (palm oil) at a depth of cut of 0.4 mm and feed rate of 0.6 mm/rev.
Formation of Nitrides and Carbides on Titanium Alloy Surface through EDM
Authors: Ndaliman Mohammed Baba , Khan Ahsan Ali , Mohammad Yeakub Ali
Published: October 2012

In this investigation, electrical discharge machining (EDM) was done with Cu-TaC powder metallurgy (PM) electrode and urea solution dielectric fluid. The main objective is to improve the surface wear property of Ti-6Al-4V alloy through the formation of hard ceramic compounds on its surface during EDM. The experiments were conducted with peak current, Ip (3.5, 5.5 A) and pulse duration, ton (3.3, 5.3 µsec) as the machining variables. The outputs investigated are surface characteristics and micro-hardness. The formation of nitrides, carbides and oxides of tantalum and titanium on the EDMed surface was confirmed. The highest micro-hardness of 902.2 Hv was obtained with Ip of 5.5 A and ton of 3.3 µsec.
Optimization of Forecasting Moving Average Error in Probabilistic Demand Using Genetic Algorithm Based Fuzzy Logic
Authors: Saleh Chairul , Andi Purnomo Muhammad Ridwan , Mukti Asih Hayati
Published: October 2012

Demand forecasting is one of the most critical factors in production planning. The uncertain demand, which is the basic idea of planning the production level, nowadays is one of serious problems. The inaccurate demand forecasting could affect to excess production or shortage stocks which led to lost sales. Usually, the forecasted result is hard to represent real condition. Some studies already conducted related to fuzzy time series, each of them has its own advantages and disadvantages compared to other approaches. This research presents the combination of simple moving average forecasting and fuzzy logic model to demand forecast. Then, genetic algorithm (GA) is applied to optimize the mean square error (MSE) inside the fuzzy system. The MSE before and after GA optimization is 0,2192 and 0,1821, respectively.
Reducing Non-Value Added Process for an Automotive Component Using Finite Element Modeling
Authors: Jaafar Roseleena , Mohd Salleh Farrahshaida , Tharazi Izdihar , Omar Abdul Rahman
Published: October 2012

The research work focuses on sheet metal stamping process simulation of an automotive component known as bracket assembly upper spring made from low carbon steel and has axis-symmetrical cup shape that employs four multi-stage drawing processes. Non-value added drawing stages (optimization process) reduced and portrayed from the formability simulation result using finite element modeling (FEM) method. The modified design, with reduction of one draw stage, showed that the risk of the component to form cracks is lesser, the material elements are further away from the failure zone of the forming limit diagram (FLD) and it meets the requirement for minimum thickness. The FEM simulation was able to predict the formability and optimize the design of a sheet metal forming process that lowered the product cost and improve cycle time.
The Effect of Internal through Coolant on Grinding Performance on AISI1020 Mildsteel
Authors: Rahim Erween Abdul , Mohid Z. , Rahman A.H.A. , Bahman M.F.
Published: October 2012

This paper presents the experimental result of grinding performance with an internal through coolant supply. Using this method, the coolant is delivered through the grinding wheel and this concept will allowed the coolant supplied directly to the contact zone. The experiment has been conducted on thin plate of AISI1020 mild steel, to ensure the effectiveness when using internal through coolant supply and the grinding result using internal through. The result of internal through coolant supply was compared with an external coolant supply. It was revealed that the temperature was lower and surface roughness was smaller when the proposed coolant supply concept used.
Predicting Surface Roughness with Respect to Process Parameters Using Regression Analysis Models in End Milling
Authors: Adesta Erry Yulian Triblas , Al Hazza Muataz H.F. , Suprianto M.Y. , Riza Muhammad
Published: October 2012

Surface roughness affects the functional attributes of finished parts. Therefore, predicting the finish surface is important to select the cutting levels in order to reach the required quality. In this research an experimental investigation was conducted to predict the surface roughness in the finish end milling process with higher cutting speed. Twenty sets of data for finish end milling on AISI H13 at hardness of 48 HRC have been collected based on five-level of Central Composite Design (CCD). All the experiments done by using indexable tool holder Sandvick Coromill R490 and the insert was PVD coated TiAlN carbide. The experimental work performed to predict four different roughness parameters; arithmetic mean roughness (Ra), total roughness (Rt), mean depth of roughness (Rz) and the root mean square (Rq).
NOVEL AGENTS AND EMERGING STRATEGIES FOR TARGETING THE B-CELL RECEPTOR PATHWAY IN CLL
Authors: Efremov Dimitar , Wiestner Adrian , Laurenti Luca
Published: October 2012

Chronic lymphocytic leukemia (CLL) is a disease of malignant CD5+ B lymphocytes that are characterized by frequent expression of autoreactive B-cell receptors (BCRs) and marked dependence on microenvironmental signals for proliferation and survival. Among the latter, signals propagated through the BCR are believed to play a key role in leukemia initiation, maintenance and evolution. Drugs that can disrupt these signals have recently emerged as potential therapeutic agents in CLL and several of them are currently being evaluated in clinical trials. Particularly promising clinical responses have been obtained with inhibitors of the kinases SYK, BTK, and PI3Kδ, which function by blocking BCR signal transduction. In addition, recent studies focusing on the phosphatase PTPN22, which is involved in the pathogenesis of multiple autoimmune diseases and is markedly overexpressed in CLL cells, suggest that it may be possible in the future to develop strategies that will selectively reprogram BCR survival signals into signals that induce leukemic cell death. This review focuses on the biological basis behind these strategies and highlights some of the most promising BCR-targeting agents in ongoing preclinical and clinical studies.
Accessing community health services: challenges faced by poor people with disabilities in a rural community in South Africa
Authors: Grut Lisbet , Mji Gubela , Braathen Stine H. , Ingstad Benedicte
Published: October 2012

Poor people with disabilities who live in poor rural societies experience unique problems in accessing health services. Their situation is influenced by multiple factors which unfold and interplay throughout the person’s life course. The difficulties do not only affect the person with a disability and his or her family, but also impact on the relevant care unit. The barriers are rooted in a life in poverty, upheld and maintained by poverty-reinforcing social forces of the past and the present, and reinforced by the lack of the person’s perspective of the health services. This article explores how difficulties may interact and influence access to and utilisation of health services, and how this may render health services out of reach even when they are available. The study reveals that non-compliance is not necessarily about neglect but could as well be a matter of lived poverty. The study was based on in-depth interviews with people with disabilities and family members, and semi-structured interviews with health personnel. The data analysis is contextual and interpretive. When offering health services to people with disabilities living in resource-poor settings, services should take into consideration the person’s history, the needs, and the resources and abilities of the family group. Rethinking access to health services should transcend a narrow medical institutionalization of health professional’s training, and include a patient’s perspective and a social vision in understanding and practice. Such rethinking requires health service models that integrate the skills of health professionals with the skills of disabled people and their family members. Such skills lie dormant at community level, and need to be recognized and utilized.
The Impact of Early Commitment on Games Played: Evidence from College Football Recruiting
Authors: Bricker Jesse , Hanson Andrew
Published: October 2012

We use data on athletic scholarship acceptance decisions to show that high school football players signal their ability level by delaying commitment. Although colleges can obtain information about student athletes, National Collegiate Athletic Association regulations limit information flow, making private information an important component of the scholarship market. Using ordinary least squares, censored regression, and negative binomial estimation, we show that for a given observed ability level, committing to a scholarship offer early is associated with less playing time after acceptance. In one season and at a typical average early signing date, early‐committing athletes played in 0.21 fewer games per season, or about 4% of the average number of games played.
Patentability and Knowledge Spillovers of Basic R&D
Authors: Chu Angus C. , Furukawa Yuichi
Published: October 2012

This study develops a research and development (R&D)–based growth model with basic and applied research to analyze the growth and welfare effects of two patent instruments: (i) the patentability of basic R&D and (ii) the division of profit between basic and applied researchers. We find that for the purpose of stimulating basic R&D and economic growth simultaneously, increasing the share of profit assigned to basic researchers is more effective than raising the patentability of basic R&D, which has either a negative effect or an inverted‐U effect on technological progress. However, a benevolent patent authority requires both patent instruments to achieve the socially optimal allocation in the decentralized economy.
The CEO Arms Race
Authors: Gritsko Natalia , Kozlova Valentina , Neilson William , Wichmann Bruno
Published: October 2012

This article constructs a game‐theoretic model in which high chief executive officer (CEO) pay emerges as the outcome of an arms race, with each firm hiring a highly paid CEO to protect its competitive position against rivals who also hire highly paid CEOs. For an arms race to emerge, highly paid CEOs must generate idiosyncratic, privately known internal effects on profit, and CEO pay disparities must also generate asymmetric profit differences from external effects beyond the simple differences in pay. If the distribution of internal effects satisfies a key uniformity condition, an arms race emerges as the only equilibrium of the game.
Go West Young Man: Self‐Selection and Endogenous Property Rights
Authors: Jaworski Taylor , Wilson Bart J.
Published: October 2012

If, as Hume argues, property is a self‐referring custom of a group of people, then property rights depend on how that group forms and orders itself. In this article we investigate how people construct a convention for property in an experiment in which groups of self‐selected individuals can migrate between three geographically separate regions. To test a hypothesis of Demsetz's, we vary across two treatments the external benefits of migrating. We find that self‐selection has a powerful effect on establishing conventions of property and begetting increases in wealth through exchange and specialization. We also find support for the Demsetz hypothesis.
Extreme ozone depletion in the 2010–2011 Arctic winter stratosphere as observed by MIPAS/ENVISAT using a 2-D tomographic approach
Authors: Arnone E. , Castelli E. , Papandrea E. , Carlotti M. , Dinelli B. M.
Published: October 2012

Abstract. We present observations of the 2010–2011 Arctic winter stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. Limb sounding infrared measurements were taken by MIPAS during the Northern polar winter and into the subsequent spring, giving a continuous vertically resolved view of the Arctic dynamics, chemistry and polar stratospheric clouds (PSCs). We adopted a 2-D tomographic retrieval approach to account for the strong horizontal inhomogeneity of the atmosphere present under vortex conditions, self-consistently comparing 2011 to the 2-D analysis of 2003–2010. Unlike most Arctic winters, 2011 was characterized by a strong stratospheric vortex lasting until early April. Lower stratospheric temperatures persistently remained below the threshold for PSC formation, extending the PSC season up to mid-March, resulting in significant chlorine activation leading to ozone destruction. On 3 January 2011, PSCs were detected up to 30.5 ± 0.9 km altitude, representing the highest PSCs ever reported in the Arctic. Through inspection of MIPAS spectra, 83% of PSCs were identified as supercooled ternary solution (STS) or STS mixed with nitric acid trihydrate (NAT), 17% formed mostly by NAT particles, and only two cases by ice. In the lower stratosphere at potential temperature 450 K, vortex average ozone showed a daily depletion rate reaching 100 ppbv day−1. In early April at 18 km altitude, 10% of vortex measurements displayed total depletion of ozone, and vortex average values dropped to 0.6 ppmv. This corresponds to a chemical loss from early winter greater than 80%. Ozone loss was accompanied by activation of ClO, associated depletion of its reservoir ClONO2, and significant denitrification, which further delayed the recovery of ozone in spring. Once the PSC season halted, ClO was reconverted primarily into ClONO2. Compared to MIPAS observed 2003–2010 Arctic average values, the 2010–2011 vortex in late winter had 15 K lower temperatures, 40% lower HNO3 and 50% lower ozone, reaching the largest ozone depletion ever observed in the Arctic. The overall picture of this Arctic winter was remarkably closer to conditions typically found in the Antarctic vortex than ever observed before.
Planetary waves in the upper stratosphere and lower mesosphere during 2009 Arctic major stratospheric warming
Authors: Kishore P. , Velicogna I. , Venkat Ratnam M. , Jiang J. H. , Madhavi G. N.
Published: October 2012

Abstract. The AURA-MLS daily mean temperatures and zonal wind from NASA-MERRA reanalysis for latitudes between 60° N and 80° N are used to investigate the planetary wave (PW) characteristics in the stratosphere and lower mesosphere during sudden stratospheric warming (SSW) (November 2008 to March 2009). Here, we used a novel method called empirical mode decomposition (EMD) to extract the PWs from the temperature data. The EMD is an interesting approach to decompose signals into locally periodic components, the intrinsic mode functions (IMFs), and will easily identify the embedded structures, even those with small amplitudes. The spectral analysis reveals prevailing planetary wave periods of ~6-day, ~8-day, ~15-day, and ~21–23-day in IMFs 1, 2, 3, and 4, respectively. Clear upward propagation of these waves (20–30 days) is observed, suggesting that sources for these oscillations are in the troposphere.
Stable isotope and trace element investigation of two contemporaneous annually-laminated stalagmites from northeastern China surrounding the "8.2 ka event"
Authors: Wu J. Y. , Wang Y. J. , Cheng H. , Kong X. G. , Liu D. B.
Published: October 2012

Abstract. The prominent "8.2 ka event" was well documented in the Greenland ice cores. It remains unclear, however, about its duration, structure and forcing mechanism at low- to mid-latitude regions. Here we use the physical and geochemical data of stalagmites from the Nuanhe Cave in Liaoning Province, northeastern China, to reconstruct a detailed history of East Asian monsoons covering the entire duration of the event. High-resolution chronologies of two contemporaneous stalagmites, each consisting of at least 770 yr annual growth bands, were established by calibrating and anchoring the floating band-counting ages against five high-precision 230Th dates. Two oxygen isotope profiles replicate each other on annual-decadal timescales despite their difference in growth rates, indicating that the δ18O variability has a climatic origin largely associated with changes in the rainfall δ18O from the West Pacific during summer season. A signal from the "8.2ka event" was faint in our δ18O records, not as significant as Indian monsoon dominated stalagmite δ18O records from Qunf in Oman and Dongge in Southern China. However, our δ13C and Ba/Ca profiles, as indicators of local environmental changes, provide strong support for a climate reversal centred at 8.2 ka BP, which is likely controlled by winter monsoon circulations via the westerly winds associated with North Atlantic climate. Therefore, we concluded that the winter- and summer-Asian monsoons responded independently to the high northern latitude climate.
A new global reconstruction of temperature changes at the Last Glacial Maximum
Authors: Annan J. D. , Hargreaves J. C.
Published: October 2012

Abstract. Some recent compilations of proxy data both on land and ocean (MARGO Project Members, 2009; Bartlein et al., 2011; Shakun et al., 2012), have provided a new opportunity for an improved assessment of the overall climatic state of the Last Glacial Maximum. In this paper, we combine these proxy data with the ensemble of structurally diverse state of the art climate models which participated in the PMIP2 project (Braconnot et al., 2007) to generate a spatially complete reconstruction of surface air (and sea surface) temperatures. We test a variety of approaches, and show that multiple linear regression performs well for this application. Our reconstruction is significantly different to and more accurate than previous approaches and we obtain an estimated global mean cooling of 4.0 ± 0.8 °C (95% CI).
Palaeostages of the Caspian Sea as a set of regional benchmark tests for the evaluation of climate model simulations
Authors: Kislov A. , Panin A. , Toropov P.
Published: October 2012

Abstract. Oscillations of the level of the Caspian Sea (CS) primarily stem from variations in runoff from the Volga River. Therefore, changes in the level of the CS can be used to assess the ability of climate models to reproduce the water budget over the East European Plain. We compare observed or reconstructed CS level positions during the Last Glacial Maximum (LGM), Holocene and modern periods with the CS level positions calculated based on simulations in experiments using the CMIP5/PMIP3 protocol. The proxy dataset comprises a number of detailed maps of the CS for the main regression stages and transgression stages during the last 30 ka together with information about sea-level positions. The results show poor correspondence between the model simulations of decadal- and centennial-scale level oscillations and proxy reconstructions. We propose that such discrepancies can be caused by insufficient sensitivity of the climate models used. The modelled data could be verified based on how well the models simulated the sharp decrease of the Volga River runoff during the LGM, which caused a large decline of the CS level.
Carbon farming in hot, dry coastal areas: an option for climate change mitigation
Authors: Becker K. , Wulfmeyer V. , Berger T. , Gebel J. , Münch W.
Published: October 2012

Abstract. We present a comprehensive, interdisciplinary project which demonstrates that large-scale plantations of Jatropha curcas – if established in hot, dry coastal areas around the world – could capture 17–25 tonnes of carbon dioxide per hectare per year from the atmosphere (averaged over 20 yr). Based on recent farming results it is confirmed that the Jatropha curcas plant is well adapted to harsh environments and is capable of growing alone or in combination with other tree and shrub species with minimal irrigation in hot deserts where rain occurs only sporadically. Our investigations indicate that there is sufficient unused and marginal land for the widespread cultivation of Jatropha curcas to reduce significantly the current upward trend in atmospheric CO2 levels. In a system in which desalinated seawater is used for irrigation and for delivery of mineral nutrients, the sequestration costs were estimated to range from 42–63 € per tonne CO2. This result makes carbon farming a technology that is competitive with carbon capture and storage (CCS). In addition, high-resolution simulations using an advanced land-surface-atmosphere model indicate that a 10 000 km2 plantation could produce a reduction in mean surface temperature and an onset or increase in rain and dew fall at a regional level.
TopoSUB: a tool for efficient large area numerical modelling in complex topography at sub-grid scales
Authors: Fiddes J. , Gruber S.
Published: October 2012

Abstract. Mountain regions are highly sensitive to global climate change. However, large scale assessments of mountain environments remain problematic due to the high resolution required of model grids to capture strong lateral variability. To alleviate this, tools are required to bridge the scale gap between gridded climate datasets (climate models and re-analyses) and mountain topography. We address this problem with a sub-grid method. It relies on sampling the most important aspects of land surface heterogeneity through a lumped scheme, allowing for the application of numerical land surface models (LSMs) over large areas in mountain regions or other heterogeneous environments. This is achieved by including the effect of mountain topography on these processes at the sub-grid scale using a multidimensional informed sampling procedure together with a 1-D lumped model that can be driven by gridded climate datasets. This paper provides a description of this sub-grid scheme, TopoSUB, and assesses its performance against a distributed model. We demonstrate the ability of TopoSUB to approximate results simulated by a distributed numerical LSM at around 104 less computations. These significant gains in computing resources allow for: (1) numerical modelling of processes at fine grid resolutions over large areas; (2) efficient statistical descriptions of sub-grid behaviour; (3) a "sub-grid aware" aggregation of simulated variables to coarse grids; and (4) freeing of resources for computationally intensive tasks, e.g., the treatment of uncertainty in the modelling process.
Trends in rainfall erosivity in NE Spain at annual, seasonal and daily scales, 1955–2006
Authors: Angulo-Martínez M. , Beguería S.
Published: October 2012

Abstract. Rainfall erosivity refers to the ability of precipitation to erode soil, and depends on characteristics such as its total volume, duration, and intensity and amount of energy released by raindrops. Despite the relevance of rainfall erosivity for soil degradation prevention, very few studies have addressed its spatial and temporal variability. In this study the time variation of rainfall erosivity in the Ebro Valley (NE Spain) is assessed for the period 1955–2006. The results show a general decrease in annual and seasonal rainfall erosivity, which is explained by a decrease of very intense rainfall events whilst the frequency of moderate and low events increased. This trend is related to prevailing positive conditions of the main atmospheric teleconnection indices affecting the West Mediterranean, i.e. the North Atlantic Oscillation (NAO), the Mediterranean Oscillation (MO) and the Western Mediterranean Oscillation (WeMO).
Enseigner dans un programme universitaire innovant : de nouveaux rôles à apprivoiser, des actes pédagogiques à diversifier
Authors: St-Pierre Lise , Bédard Denis , Lefebvre Nathalie
Published: October 2012

Cette recherche vise à décrire, à partir d’observations empiriques, les rôles exercés et les actes pédagogiques effectués par les enseignantes et les enseignants engagés dans quatre programmes universitaires canadiens jugés innovants. L’observation directe en classe a permis de recueillir leurs propos qui ont été analysés à l’aide de deux grilles construites progressivement au cours de l’étude: la liste des dimensions théoriques et la grille des niveaux de centration sur l’apprentissage. Les résultats obtenus démontrent que les rôles et les actes pédagogiques observés apparaissent moins diversifiés et moins centrés sur l’apprentissage que ce qui est attendu dans un contexte novateur de formation.
This research, based on empirical observations, describes the roles and teaching acts carried out by professors engaged in four innovative university programs in Canada. Classrooms observations were used to collect data, which were then analyzed using two grids built progressively during the study: a list of theoretical dimensions and a grid showing degrees of focus on learning. In terms of results, the roles and actions of the four university professors were found to be less diversified and less centered on student learning than was expected from their innovative instructional context.
A Sterile Elastic Exsanguination Tourniquet is Effective in Preventing Blood Loss during Hemodialysis Access Surgery
Authors: Ladenheim Eric , Krauthammer Juergen , Agrawal Siddartha , Lum Craig , Chadwick Nathan
Published: October 2012

Purpose

We report the first use of a sterile elastic exsanguination tourniquet (SET) in performing hemodialysis vascular access procedures in 27 patients. The main advantages of this tourniquet are the reduction of blood loss and need for possible transfusions. Additional benefits are the near-perfect exsanguination and excellent exposure of the operative field.

Methods

This SET is a sterile elastic stockinet device that rolls up the arm starting from the hand by pulling on two handles. The elastic silicone ring provides sufficient pressure (220 ± 30 mmHg) to block arterial flow into the limb. The stockinet can be cut to provide access to the incision area while providing an additional sterile cover over the rest of the limb.

Results

No transfusions were required in any patients. Minor adverse effects occurred in four patients, including a twisted vessel, a bleeding vascular branch, a tear in atrophic arm skin, and pain, all of which had resolved on subsequent follow-up. Operational recommendations to avoid these adverse effects are outlined.

Conclusions

We conclude that this sterile elastic exsanguination tourniquet is effective and safe in preventing bleeding during upper extremity hemodialysis vascular access procedures.
Toward a Theory of Childhood Learning Disorders, Hyperactivity, and Aggression
Authors: Mawson Anthony R.
Published: October 2012

Learning disorders are often associated with persistent hyperactivity and aggression and are part of a spectrum of neurodevelopmental disorders. A potential clue to understanding these linked phenomena is that physical exercise and passive forms of stimulation are calming, enhance cognitive functions and learning, and are recommended as complementary treatments for these problems. The theory is proposed that hyperactivity and aggression are intense stimulation-seeking behaviors (SSBs) driven by increased brain retinergic activity, and the stimulation thus obtained activates opposing nitrergic systems which inhibit retinergic activity, induce a state of calm, and enhance cognition and learning. In persons with cognitive deficits and associated behavioral disorders, the retinergic system may be chronically overactivated and the nitrergic system chronically underactivated due to environmental exposures occurring pre- and/or postnatally that affect retinoid metabolism or expression. For such individuals, the intensity of stimulation generated by SSB may be insufficient to activate the inhibitory nitrergic system. A multidisciplinary research program is needed to test the model and, in particular, to determine the extent to which applied physical treatments can activate the nitrergic system directly, providing the necessary level of intensity of sensory stimulation to substitute for that obtained in maladaptive and harmful ways by SSB, thereby reducing SSB and enhancing cognitive skills and performance.
Germination and Seedling Growth of Some Chickpea Cultivars (Cicer arietinum L.) under Salinity Stress
Authors: A.A. Kandil  , A.E. Sharief  , S.R.H. Ahmed
Published: October 2012

In order to study the response of some Chickpea (Cicer arietinum L.) cultivars i.e. Giza 1, Giza 2, Giza 3, Giza 3, Giza 4, Giza 195, Giza 531, and Chickpea stand1to germination under salinity concentrations i.e. control treatment, 4, 8, 12, 16, and 20 dSm-1 NaCl and to confirm the seedling growth performance. A laboratory experiment was laid out at Giza Central Seed Testing Laboratory of Central Administration for Seed Certification, Ministry of Agriculture, Egypt. Giza 3 cultivar exceeded other cultivars in germination percentage, germination index, seedling vigor index, shoot length, shoot and root dry weight followed by Giza 1 and Giza 2 cultivars. Giza 2 cultivar recorded highest mean germination time, followed by chickpea stand 1 and Giza 4 cultivars. Giza 195 cultivar exceeded other cultivars in root length and Giza 531 and Giza 1 cultivars surpassed other cultivars in shoot fresh weight. Chickpea stand 1 and Giza 195 cultivars surpassed other cultivars in seedling height reduction and Giza 1, Giza 2, Giza 3, and Giza 4, came in the second rank. However, the lowest percentages of seedling height reduction were obtained from Giza 531 cultivar. Increasing salinity levels from 0 to 20 dSm-1 significantly decreased germination percentage, germination index, seedling vigor index, shoot and root length, shoot and root fresh weight, shoot and root dry weight and relative dry weight. The control treatment recorded highest averages of these characters, vice versa mean germination time and seedling height reduction. Germination index, seedling vigor index, shoot and root length (cm), shoot and root fresh weight (mg), shoot and root dry weight (mg), seedling height reduction % and relative dry weight % significantly affected by the interaction between chickpea cultivars and salinity concentration. Giza 3, Giza 1 and Giza 2 cultivars were more tolerant to salinity and recommended to be used in breeding program for enhancing chickpea cultivation in newly reclaimed soils.
Seasonal Variations and Characterization of Solid Aerosols Related to Faisalabad (Pakistan) Environment
Authors: Muhammad Attique Khan Shahid  , Khadim Hussain  , Mariam Saeed Awan
Published: October 2012

Black solid aerosols were monitored continuously at Faisalabad using Gaussian dispersion model and nucleation model. Data for one year 2006 was analyzed here keeping in view the meteorological and climatological conditions of Faisalabad co-relating them with concentration gradient. Winter has minimum concentration, i.e. equivalent to background level followed by summer (598.80 μmg/m3), Moon Soon (2762.00 μmg/m3) and finally Post Moon Soon (8863.00 mg/m3). Temperature and pressure gradients both were negative co-relationed with black solid aerosols. These results were not in accordance with other studies, the reason may be the complexity of the Faisalabad environment on account of its geographical, geological and industrial setup confirmed by longitudinal, latitudinal effects and mix plume behavior. A positive co-relationship between biomass burning and seasonal variation i.e. low concentration of particulate matter i.e., 637.30 μg/m3 in summer and high in winter such as 3954 μg/m3.
Challenges and opportunities for the implementation of virological testing in resource‐limited settings
Authors: Roberts Teri , Bygrave Helen , Fajardo Emmanuel , Ford Nathan
Published: October 2012

Though the advantages of routine virological monitoring for patients on anti‐retroviral therapy have been established, cost and complexity limit its full implementation. Monitoring is important for diagnosing virological failure early on, before the development of drug resistance mutations, and to trigger early adherence interventions. Simple and cost‐effective viral load tests that facilitate simplification and decentralization of testing and strategies, such as the use of dried blood spots and pooled sample testing, which further aid simplification, are becoming available. In addition, replacing immunological monitoring with virological monitoring in non‐viremic patients in a phased manner will reduce the costs associated with dual immuno‐virological monitoring. Going forward, the simplification of testing paired with price reducing strategies that will allow for healthy competition between multiple manufacturers will enable the implementation of viral load testing in resource‐poor settings. It is important that future HIV and AIDS treatment guidelines provide clear recommendations for routine virological monitoring and that governments and donors fund the implementation of accurate and operationally proven testing platforms in a comprehensive manner.