bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance analysis of probabilistic soft SSDF attack in cooperative spectrum sensing
Authors: Zhang Linyuan , Wu Qihui , Ding Guoru , Feng Shuo , Wang Jinlong
Published: May 2014

In cognitive radio networks, spectrum sensing data falsification (SSDF) attack is a crucial factor deteriorating the detection performance of cooperative spectrum sensing. In this paper, we propose and analyze a novel probabilistic soft SSDF attack model, which goes beyond the existing models for its generalization. Under this generalized SSDF attack model, we firstly obtain closed form expressions of global sensing performance at the fusion center. Then, we theoretically evaluate the performance of the proposed attack model, in terms of destructiveness and stealthiness, sequentially. Numerical simulations match the analytical results well. Last but not least, an interesting trade-off between destructiveness and stealthiness is discovered, which is a fundamental issue involved in SSDF attack, however, ignored by most of the previous studies.
Reactivity to fearful expressions of familiar and unfamiliar people in children with autism: an eye-tracking pupillometry study
Authors: Nuske Heather J , Vivanti Giacomo , Dissanayake Cheryl
Published: May 2014

Background

Individuals with autism are often reported to have difficulty with emotion processing. However, clinical and experimental data show that they are sensitive to familiarity; for example, they show normative attachment to familiar people, and have normative brain activity in response to familiar faces. To date, no study has measured their reactivity to the emotions of familiar vs. unfamiliar people. Thus, our aim was to determine whether individuals with autism would show normative reactivity to emotion in familiar people.

Methods

Participants were 21 children with autism and 21 children with typical development, aged two to five years, matched on age and gender. The children observed videos of familiar people (their child-care teachers) and unfamiliar people expressing fear, whilst their visual attention and pupillary reactions were recorded (the latter as an index of emotional reactivity), using eye tracking technology.

Results

The children with autism showed normative pupillary reactions (peak magnitude) to fear expressed by familiar people, but a reduced response to fear expressed by unfamiliar people. However, across familiarity conditions, the children with autism had longer latency peak responses than the typically developing children. This pattern of findings was independent of cognitive factors or visual attention as visual attention by group was not related to familiarity condition. The children with autism had reduced visual attention to neutral faces; however, on fearful faces there were no group differences. Abnormalities in pupillary reactivity in the autism group were related to less prosocial behaviour and more severe play and communication deficits.

Conclusions

Children with autism were less atypical in their responses to fearful expressions of people they know, arguing against a pervasive emotional impairment in autism, but rather one that may be mediated by familiarity.
A 90Y-labelled anti-ROBO1 monoclonal antibody exhibits antitumour activity against hepatocellular carcinoma xenografts during ROBO1-targeted radioimmunotherapy
Authors: Fujiwara Kentaro , Koyama Keitaro , Suga Kosuke , Ikemura Masako , Saito Yasutaka , Hino Akihiro , Iwanari Hiroko , Kusano-Arai Osamu , Mitsui Kenichi , Kasahara Hiroyuki , Fukayama Masashi , Kodama Tatsuhiko , Hamakubo Takao , Momose Toshimitsu
Published: May 2014

Background

ROBO1 is a membrane protein that functions in axon guidance. ROBO1 contributes to tumour metastasis and angiogenesis and may have potential as a target protein of immunotherapy because ROBO1 is specifically expressed at high levels in hepatocellular carcinoma. In this study, we examined biodistribution and radioimmunotherapy (RIT) using a radioisotope-labelled anti-ROBO1 monoclonal antibody (MAb) against hepatocellular carcinoma models.

Methods

ROBO1-positive HepG2 human hepatocellular carcinoma xenograft nude mice were used in this study. We conjugated anti-ROBO1 MAb with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and the conjugates were labelled with 111In and 90Y. To study biodistribution, the 111In-DOTA-anti-ROBO1 MAb was injected into HepG2 xenograft mice via the tail vein. To evaluate any antitumour effect, a RIT study was performed, and the 90Y-DOTA-anti-ROBO1 MAb was injected via the tail vein. Tumour volume, mouse weight, and blood cell count were periodically measured throughout the experiments. The tumours and organs of mice were collected, and a histopathological analysis was carried out.

Results

The tumour uptake of 111In-anti-ROBO1 MAb in HepG2 xenograft mice was 15.0% ± 0.69% injected dose per gram at 48 h after injection.

Immunotherapy with cold-anti-ROBO1 MAb (70 μg) did not cause a significant antitumour effect. RIT with 6.7 MBq of 90Y-anti-ROBO1 MAb caused significant tumour growth suppression. Transient body weight loss and bone-marrow suppression were observed. Histopathological analyses of tumours revealed the fatal degeneration of tumour cells, significant reduction of the Ki-67 index, and an increase of the apoptosis index. Normal organs showed no significant injury, but a transient reduction of hematopoietic cells was observed in the spleen and in the sternal bone marrow.

Conclusions

These results suggest that RIT with 90Y-anti-ROBO1 MAb is a promising treatment for ROBO1-positive hepatocellular carcinoma.
Statistical Evaluation of Non-Linear Parameter Estimation Procedures for Adsorption Equilibrium Models
Authors: Cassol Guilherme Ozorio , Gallon Roger , Schwaab Marcio , Barbosa-Coutinho Elisa , Júnior João B. Severo , Pinto José Carlos
Published: May 2014

Adsorption equilibrium is a fundamental concept in the adsorption science and relates the equilibrium between the quantity of the adsorbed material and its concentration in the bulk phase. Several models have been proposed for prediction of adsorption equilibrium and all models depend on parameters whose values must be estimated from available experimental data. Although linear parameter estimation procedures can be used for model fitting, through transformation of available experimental data and model parameters, non-linear parameter estimation procedures lead to more reliable results and allow for direct comparison of results obtained with different adsorption equilibrium models. The main objective of this work is to present and compare different non-linear procedures for parameter estimation of adsorption equilibrium models, based on theoretical arguments and also on the numerical estimation of adsorption equilibrium parameters, using available experimental data for adsorption of methylene blue onto activated carbon. The results obtained indicate that the best parameter estimation procedure is the one that relies on available equilibrium concentrations in the bulk phase as a function of the fluid volume, adsorbent mass and initial concentrations in the bulk phase, without transformation of measured experimental values and model parameters. Besides, it is shown that parameter estimates should be obtained through proper minimization of weighted least-squares objective function, in accordance with maximum likelihood procedures.
Development of Semi-Static Steam Process for the Production of Sludge-Based Adsorbents
Authors: El-Sayed Yehya A. , Loughlin Kevin F. , Rehman Saeed ur , Abouelnasr Dana , Al-Zubaidy Isam
Published: May 2014

In this study, a specially developed unique process was used to prepare sludge-based activated adsorbents (SBAs) from municipal sewage sludge collected from a wastewater treatment plant in Sharjah. A reaction chamber is designed to allow the carbonization and activation of sewage sludge in a saturated steam environment generated inside the chamber (semi-static). The semi-static steam process is carried out in the absence of any external gas flow into the reaction chamber. The activated sample is subjected to acid treatment. Other SBA samples are also prepared at the same temperatures using a conventional method in the presence of external flow of nitrogen gas. The surface chemistry for the SBA samples is characterized using Boehm titrations, pH measurement, ash content and scanning electron microscope integrated with energy-dispersive spectroscopy (EDAX). The semi-static steam method results in the formation of an SBA sample with acidic surface and higher carbon content as compared with the samples prepared by the conventional method. The metal contents of the SBAs are significantly different and depend on the methods of preparation. Nitrogen sorption isotherms are measured and used for the analysis of structure and porosity. The BET surface area for the SBA sample produced in the proposed method is calculated to be 838 m2/g. The SBA samples are then compared for adsorption efficiency of lead ions from aqueous solution, which is observed to be dependent on the microporosity and surface basicity.
Novel Liquid-Liquid-Solid Microextraction Using Molecularly Imprinted Polymer Monolithic Fibres and its Application to the Extraction of s-Triazine Herbicides from Water Samples
Authors: Chen Jun , Bai Lianyang , Zhang Li , Hu Mei , Zhang Yuping
Published: May 2014

A novel method to quickly prepare molecularly imprinted polymer (MIP) monolithic fibres is developed using microwave irradiation. The well-known water-compatibility problem of MIP is overcome by liquid-liquid-solid microextraction (LLSME). The atrazine (ATR) MIP fibre was obtained after silica was etched away with a controlled length of 1 cm, and subsequently characterized by scanning electron microscopy. Main factors affecting the selective extraction, including extraction time, desorption time, extraction and desorption solvents, were investigated for LLSME procedures in detail. The selectivity was also evaluated using the ATR template molecule and its structurally related compounds, including 2-amino-4-methoxy-6-methyl-1,3,5-triazine, terbuthylazine, ametryn and metribuzin pesticides. The extraction ratio of target pesticides in ATR-imprinted polymeric monolithic fibre was increased to more than 10 times than that in non-imprinted polymeric monolithic fibre. The resultant fibres coupled by HPLC were successfully applied to detect ATR and its analogue pesticides with recoveries in the range of 68.3–92.6%. In addition, the LLSME technique was proved to be effective in extracting spiked TRI, ATR, AME and TER in lake water. This method provided a satisfactory solution for the simple, rapid, selective and sensitive pre-treatment of trace herbicides in various aqueous samples. The results demonstrate that the proposed technique could solve the water compatibility problem when the MIP monolithic fibre was exposed directly to a non-polar solvent above the aqueous solution.
Eigen Frequencies of a Vertical Axis Wind Turbine Tower Made of Laminated Wood and the Effect upon Attaching Guy Wires
Authors: Möllerström Erik , Ottermo Fredric , Hylander Jonny , Bernhoff Hans
Published: May 2014

Eigen frequencies of a vertical axis wind turbine tower made out of laminated wood which are both bolted to the ground and supported by guy wires are studied and compared. Using beam theory, an analytical model taking the guy wires into account for calculating the first mode eigen frequency of the tower has been derived. The analytical model is then evaluated by comparing with FEM-simulations and measurements performed on the actual tower. The model is found to be reasonably accurate keeping in mind that the estimated masses and second moments of area are somewhat rough. Furthermore the model can be used to give an indication of the magnitude of change in eigen frequency when modifying a tower or guy wire property.
Design and Optimization of Isolated Wind-Battery Systems Incorporating Multiple Wind Generators
Authors: Roy Anindita , Kedare Shireesh B , Bandyopadhyay Santanu
Published: May 2014

Systems consisting of multiple wind-generators along with a single battery bank are a sustainable alternative for supplying the energy requirements of remote locations not connected to the national grid. In this paper, a methodology for sizing and optimizing wind-battery systems employing multiple wind turbines is proposed. Uncertainty in wind resource availability is taken into account by formulating the problem as a chance constraint. Based on a time step simulation, subject to different technical and physical design constraints, the entire solution space in terms of the system design variables viz., generator rating, rotor diameter and battery bank size for a specified number of wind turbines and reliability requirement is generated. The domain containing all feasible solutions is the design space and it is a function of system reliability requirement and the number of wind turbines. From the design space of multiple wind turbine-battery systems, it is shown that with an increase in the number of wind generators, the rotor diameter, generator rating of individual turbines as well as battery bank size can be minimized along with a benefit in the overall cost of energy (US$/kWh). Additionally, by increasing the number of wind generators it is possible to comply with a stringent power supply reliability target which would otherwise not be possible. The strength of the proposed methodology lies in the visualization of alternative solutions and identification of the minimum and the maximum limits of various system design variables.
Introduction to the Special Issue — Theoretical Advances in and Empirical Lessons on Emission Trading Schemes
Authors: Fan Ying , Eichhammer Wolfgang
Published: May 2014

Emission trading schemes (ETS) are being employed by an increasing number of countries as a market-based policy instrument to reduce greenhouse gas (GHG) emissions and so address climate change. Although traditional environmental economics has laid a strong foundation for ETS design, the existing schemes of GHG trading in different countries are facing many new challenges and critical issues still need to be explored. China, the largest greenhouse gas emitter, is currently in the process of setting up ETS pilot schemes. Learning from the ETS experiences of other countries may prove valuable. Against this background, an international conference was held in Beijing on the theoretical advances in and empirical lessons of emission trading schemes. Leading scholars from China, Germany, France, Singapore, Australia, New Zealand, and the United States presented new research findings. Ten selected papers from this conference are brought together in this Special Issue of Energy and Environment. Topics include analysing greenhouse gas emissions, the abatement potentials in key sectors, the regulation of ETS, sector coverage of ETS, interaction between ETS and other policy instruments, and between ETS and investment in carbon abatement technology. Experiences with several ETS were explored, including SO2 trading in China, carbon emissions trading in California, and several ETS pilot schemes in China.
Review of Carbon Emissions Trading Pilots in China
Authors: Duan Maosheng , Pang Tao , Zhang Xiliang
Published: May 2014

China's carbon emissions trading pilot schemes have already made significant progress, with five out of the seven pilot systems having started operation by the end of 2013. The experience in establishing and operating the pilot schemes will be valuable to the establishment of China's unified national emissions trading system in the near future. Design features of the five pilots are analyzed and compared, based on officially published documents. Aspects discussed include the establishment of the emissions cap, sector coverage, allowance allocation, data basis, compliance rules, monitoring/reporting/verification (MRV) mechanism, market intervention, offset mechanism, stakeholder consultations and legal basis. These systems are somewhat similar in cap setting, MRV mechanism and offset mechanism, but quite different in allocation approaches and market intervention. The schemes differ as well from existing international schemes as for example the European Emission Trading Scheme (EU ETS). Reasons for the different designs are briefly analyzed in a comparative manner.
Going to the Source: Using an Upstream Point of Regulation for Energy in a National Chinese Emissions Trading System
Authors: Kerr Suzi , Duscha Vicki
Published: May 2014

There are many choices within the design of an emissions trading system. In this paper we focus on one specific aspect – the point of regulation for the energy sector. This choice affects transaction costs; comprehensiveness, and hence the amount of emissions covered and the extent to which the potential cost-effectiveness gains are realised; and credibility of the system. We discuss how an ‘upstream’ energy sector emissions trading system works and present arguments for going upstream (in particular, simplicity of administration) while also discussing arguments for other points of regulation in the light of Chinese circumstances. We further present experiences with the New Zealand system, the only system that is entirely upstream for energy, showing ways to address issues that may arise with an upstream system. Ultimately the success of emissions trading depends on flexible markets that operate in a relatively free and competitive way. Simply copying others' systems in the context of a largely controlled economy such as the Chinese one is likely to be ineffective; each system must be uniquely tailored to local circumstances, possibly in China more than ever before.
Which Sectors Should Be Included in the Ets in the Context of a Unified Carbon Market in China?
Authors: Fan Ying , Wang Xu
Published: May 2014

It is crucial to determine an adequate sectoral coverage in the design of a Chinese emissions trading mechanism, as there is a huge diversity in regional economic development in China and an Emission Trading Scheme (ETS) would not initially be able to cover all sectors. This paper uses an inter-regional model to estimate the regional and sectoral abatement cost curves and simulate the operation of an emissions trading system where, like the European Union Emissions Trading Scheme (EU ETS), emissions are regulated at the point of emissions downstream where there is a large number of firms, rather than ‘upstream“. Then we build a Nash-Cournot model to analyse the influence of strategic partitioning of allowances based on the analysis of compliance cost in different sectoral coverage schemes in the unified carbon market. We take into account the allowance price, trading volumes, transaction cost, and regional differences in reduction potentials. We come to the following main conclusions: (a) the strategic partitioning of reduction requirements between trading and non-trading sectors has little impact on allowance prices and compliance cost. Despite this western regions in China are likely to receive more benefit than those in the east though the gains are limited; (b) when industrial sectors are successively included in the ETS, allowance prices range from 40–50 RMB/tonne. This approaches that in the ideal scenario in which all sectors are included; (c) the following sectors could be included in a reasonable sectoral coverage of a downstream ETS in China: mining, paper and printing, processing of petroleum, coking, processing of nuclear fuel, chemical products, metals and non-metal products, and production and supply of electric power and gas.
Emissions Trading in the Climate Policy Mix — Understanding and Managing Interactions with other Policy Instruments
Authors: Görlach Benjamin
Published: May 2014

Emissions trading promises the achievement of a pre-defined environmental outcome at least cost. If the system works and key assumptions hold, it would seem to be an “optimal” climate policy instrument. On closer inspection, however, it is less clear what constitutes an “optimal” climate policy. This paper argues that optimality involves a range of criteria beyond short-term economic efficiency, but also has to consider the longer-term dynamic efficiency, as well as the political, administrative and legal feasibility of policy instruments. The assessment of optimality is confounded by the fact that climate policy relies on a number of policy instruments. This paper argues that a policy analysis should look at the performance of the entire instrument mix, and not analyse individual instruments in isolation. Such a mix will differ from country to country – depending on political preferences, administrative capacities, or regulatory traditions. The mix is also evolving: As climate policy aims to transform entire economies, the impact of individual policy instruments in the climate policy mix grows – measured by the share of the relevant markets that they affect, the incentives they provide, or the costs they impose. As this impact grows, there is increasing interaction between policy instruments. Understanding and managing these interactions therefore becomes key for successful climate policy. Emissions trading has a particular position in this instrument mix: it directly targets the end result, i.e. emissions from the regulated sectors, inputs to the process, technologies used, or the infrastructure, where other instruments target the interim stages in the process. At the same time, emissions trading also builds on other policies, for instance through administrative and regulatory infrastructures. This paper discusses how the other policy instruments affect the functioning of an emissions trading scheme (ETS), and how this will reflect on the performance of an ETS in terms of optimality.
Kernel Parameter Selection for Support Vector Machine Classification
Authors: Liu Zhiliang , Xu Hongbing
Published: May 2014

Parameter selection for kernel functions is important to the robust classification performance of a support vector machine (SVM). This paper introduces a parameter selection method for kernel functions in SVM. The proposed method tries to estimate the class separability by cosine similarity in the kernel space. The optimal parameter is defined as the one that can maximize the between-class separability and minimize the within-class separability. The experiments for several kernel functions are conducted on eight benchmark datasets. The results demonstrate that our method is much faster than grid search with comparable classification accuracy. We also found that the proposed method is an extension of a reported method in reference [2].
A Static Traffic Grooming Scheme for IP over WDM Optical Internet
Authors: Lai Wuwen , Wang Longfei , Wang Xingwei , Huang Min
Published: May 2014

In order to improve the bandwidth utilization of IP over WDM (Wavelength Division Multiplexing) optical Internet, a static traffic grooming scheme was proposed by introducing the knowledge of fuzzy mathematics and microeconomics. It introduced the user traffic request delay satisfaction degree and the network relative cost. With the help of gaming analysis and layered graph, based on predatory search algorithm (PSA), it tried to find the optimal grooming solution with the comprehensive user QoS (Quality of Service) satisfaction degree maximized and the network relative cost minimized. It was simulated over actual network topologies and its performance was compared with certain existing traffic grooming scheme. Simulation results have shown that it is both feasible and effective with better performance.
Estimation of Heat Transfer Coefficient in Inverse Heat Conduction Problem Using Quantum-Behaved Particle Swarm Optimization with Tikhonov Regularization
Authors: Tian Na , Zhu Longchao , Lai Choi-Hong
Published: May 2014

The quantum-behaved particle swarm optimization (QPSO) with Tikhonov regularization is used to solve the inverse heat conduction problem of estimating the time dependent heat transfer coefficient of a flat plate. The prior information about the functional form of the unknown is unavailable. The estimation is based on transient temperature measurements taken by the sensors imbedded in the plate, which are used in the least square model, minimized by QPSO. The detail of choosing the best regularization parameter by L-curve method is presented. Numerical experiments are performed to test the proposed method. Effects of the location and number of sensors are also investigated. Comparison with conjugate gradient method is given as well.
Caste, asset and disaster recovery: the problems of being asset-less in disaster compensation and recovery
Authors: Irshad, S Mohammed
Published: May 2014

Damage and loss assessment is the first step towards the bringing the disaster affected community back to mainstream life. The asset is the deciding factor; hence those who do not have assets are normally excluded from compensation. In India many Dalit victims are forced to remain outside the purview of formal disaster rehabilitation. Also, the value of assets of such asset-less communities seldom figures in a damage and loss assessment, which prevents the community from attaining sustainable resiliencethus exposing them to cumulative vulnerability.
Working and mothering: interlocking locations in the caringscape
Authors: O’Hagan Clare
Published: May 2014

Drawing on empirical research with 30 ‘working mothers’, this article explores the complex inequality experienced at the intersection of motherhood with paid work in Ireland by revealing the ways in which women navigate working and caring across times and spaces. The article adds to debates about intersectionality theory by including maternity as a category for intersectional analysis. It explores women’s everyday experiences at the intersection of motherhood with paid work and reveals that women foreground motherhood in their caring activities, while minimising it in the workplace. ‘Working mothers’ demonstrate their ‘caringscapes’ (McKie et al, 2004), contain a series of interlocking locations, in and across which women work and care, and reveal the ways in which power operates to create inequalities for women who combine motherhood with paid work.
Constitutive hippocampal cholesterol loss underlies poor cognition in old rodents
Authors: Martin Mauricio G , Ahmed Tariq , Korovaichuk Alejandra , Venero Cesar , Menchón Silvia A , Salas Isabel , Munck Sebastian , Herreras Oscar , Balschun Detlef , Dotti Carlos G
Published: May 2014

Cognitive decline is one of the many characteristics of aging. Reduced long‐term potentiation (LTP) and long‐term depression (LTD) are thought to be responsible for this decline, although the precise mechanisms underlying LTP and LTD dampening in the old remain unclear. We previously showed that aging is accompanied by the loss of cholesterol from the hippocampus, which leads to PI3K/Akt phosphorylation. Given that Akt de‐phosphorylation is required for glutamate receptor internalization and LTD, we hypothesized that the decrease in cholesterol in neuronal membranes may contribute to the deficits in LTD typical of aging. Here, we show that cholesterol loss triggers p‐Akt accumulation, which in turn perturbs the normal cellular and molecular responses induced by LTD, such as impaired AMPA receptor internalization and its reduced lateral diffusion. Electrophysiology recordings in brain slices of old mice and in anesthetized elderly rats demonstrate that the reduced hippocampal LTD associated with age can be rescued by cholesterol perfusion. Accordingly, cholesterol replenishment in aging animals improves hippocampal‐dependent learning and memory in the water maze test.
Could different treatment approaches in acromegaly influence life expectancy? A comparative study between Bulgaria and Campania (Italy)
Authors: Colao Annamaria , Vandeva Silvia , Pivonello Rosario , Grasso Ludovica Francesca Stella , Nachev Emil , Auriemma Renata S , Kalinov Krasimir , Zacharieva Sabina
Published: May 2014

Background

Mortality in acromegaly strictly depends on optimal control of GH and IGF1 levels. Modern medical therapy with somatostatin analogs (SSAs) and GH receptor antagonists (GHRAs) is not available in many countries due to funding restrictions. This retrospective, comparative, cohort study investigated the impact of different treatment modalities on disease control (GH and IGF1) and mortality in acromegaly patients.

Methods

Two cohorts of patients with acromegaly from Bulgaria (n=407) and Campania, Italy (n=220), were compared, and mortality rates were evaluated during a 10-year period (1999–2008).

Results

The major difference in treatment approach between cohorts was the higher utilization of SSAs and GHRAs in Italy, leading to a decreased requirement for radiotherapy. Significantly more Italian than Bulgarian patients had achieved disease control (50.1 vs 39.1%, P=0.005) at the last follow-up. Compared with the general population, the Bulgarian cohort had a decreased life expectancy with a standardized mortality ratio (SMR) of 2.0 (95% CI 1.54–2.47) that was restored to normal in patients with disease control – SMR 1.25 (95% CI 0.68–1.81). Irradiated patients had a higher cerebrovascular mortality – SMR 7.15 (95% CI 2.92–11.37). Internal analysis revealed an independent role of age at diagnosis and last GH value on all-cause mortality and radiotherapy on cerebrovascular mortality. Normal survival rates were observed in the Italian cohort: SMR 0.66 (95% CI 0.27–1.36).

Conclusions

Suboptimal biochemical control was associated with a higher mortality in the Bulgarian cohort. Modern treatment options that induce a strict biochemical control and reduce the necessity of radiotherapy might influence the life expectancy. Other factors, possibly management of comorbidities, could contribute to survival rates.
Genome-wide screening of copy number variants in children born small for gestational age reveals several candidate genes involved in growth pathways
Authors: Canton Ana P M , Costa Sílvia S , Rodrigues Tatiane C , Bertola Debora R , Malaquias Alexsandra C , Correa Fernanda A , Arnhold Ivo J P , Rosenberg Carla , Jorge Alexander A L
Published: May 2014

Background

The etiology of prenatal-onset short stature with postnatal persistence is heterogeneous. Submicroscopic chromosomal imbalances, known as copy number variants (CNVs), may play a role in growth disorders.

Objective

To analyze the CNVs present in a group of patients born small for gestational age (SGA) without a known cause.

Patients and methods

A total of 51 patients with prenatal and postnatal growth retardation associated with dysmorphic features and/or developmental delay, but without criteria for the diagnosis of known syndromes, were selected. Array-based comparative genomic hybridization was performed using DNA obtained from all patients. The pathogenicity of CNVs was assessed by considering the following criteria: inheritance; gene content; overlap with genomic coordinates for a known genomic imbalance syndrome; and overlap with CNVs previously identified in other patients with prenatal-onset short stature.

Results

In 17 of the 51 patients, 18 CNVs were identified. None of these imbalances has been reported in healthy individuals. Nine CNVs, found in eight patients (16%), were categorized as pathogenic or probably pathogenic. Deletions found in three patients overlapped with known microdeletion syndromes (4q, 10q26, and 22q11.2). These imbalances are de novo, gene rich and affect several candidate genes or genomic regions that may be involved in the mechanisms of growth regulation.

Conclusion

Pathogenic CNVs in the selected patients born SGA were common (at least 16%), showing that rare CNVs are probably among the genetic causes of short stature in SGA patients and revealing genomic regions possibly implicated in this condition.
GENETICS IN ENDOCRINOLOGY: Genetic variation in deiodinases: a systematic review of potential clinical effects in humans
Authors: Verloop Herman , Dekkers Olaf M , Peeters Robin P , Schoones Jan W , Smit Johannes W A
Published: May 2014

Iodothyronine deiodinases represent a family of selenoproteins involved in peripheral and local homeostasis of thyroid hormone action. Deiodinases are expressed in multiple organs and thyroid hormone affects numerous biological systems, thus genetic variation in deiodinases may affect multiple clinical endpoints. Interest in clinical effects of genetic variation in deiodinases has clearly increased. We aimed to provide an overview for the role of deiodinase polymorphisms in human physiology and morbidity. In this systematic review, studies evaluating the relationship between deiodinase polymorphisms and clinical parameters in humans were eligible. No restrictions on publication date were imposed. The following databases were searched up to August 2013: Pubmed, EMBASE (OVID-version), Web of Science, COCHRANE Library, CINAHL (EbscoHOST-version), Academic Search Premier (EbscoHOST-version), and ScienceDirect. Deiodinase physiology at molecular and tissue level is described, and finally the role of these polymorphisms in pathophysiological conditions is reviewed. Deiodinase type 1 (D1) polymorphisms particularly show moderate-to-strong relationships with thyroid hormone parameters, IGF1 production, and risk for depression. D2 variants correlate with thyroid hormone levels, insulin resistance, bipolar mood disorder, psychological well-being, mental retardation, hypertension, and risk for osteoarthritis. D3 polymorphisms showed no relationship with inter-individual variation in serum thyroid hormone parameters. One D3 polymorphism was associated with risk for osteoarthritis. Genetic deiodinase profiles only explain a small proportion of inter-individual variations in serum thyroid hormone levels. Evidence suggests a role of genetic deiodinase variants in certain pathophysiological conditions. The value for determination of deiodinase polymorphism in clinical practice needs further investigation.
Dating Rare Mutations from Small Samples with Dense Marker Data
Authors: Gandolfo Luke C , Bahlo Melanie , Speed Terence P
Published: May 2014

We present a method for estimating the age of a mutation based on the genetic length of ancestral haplotypes shared between individuals carrying the mutation. The method can be reliably applied to small samples, typical of situations involving rare mutations, and makes effective use of modern high-density SNP data, thus overcoming two of the limitations with existing methods. The method provides age estimates and confidence intervals without the use of asymptotic theory and is applicable to genealogies in which the data are independent or correlated. In the correlated case we estimate the correlation directly from the data, rather than relying on a model for the genealogy. To demonstrate the method’s efficacy, we provide simulation results and compare it to other methods. The length data are obtained with a simple procedure, and an R script is available for performing the calculations.
The Principal Role of Ku in Telomere Length Maintenance Is Promotion of Est1 Association with Telomeres
Authors: Williams Jaime M , Ouenzar Faissal , Lemon Laramie D , Chartrand Pascal , Bertuch Alison A
Published: May 2014

Telomere length is tightly regulated in cells that express telomerase. The Saccharomyces cerevisiae Ku heterodimer, a DNA end-binding complex, positively regulates telomere length in a telomerase-dependent manner. Ku associates with the telomerase RNA subunit TLC1, and this association is required for TLC1 nuclear retention. Ku–TLC1 interaction also impacts the cell-cycle-regulated association of the telomerase catalytic subunit Est2 to telomeres. The promotion of TLC1 nuclear localization and Est2 recruitment have been proposed to be the principal role of Ku in telomere length maintenance, but neither model has been directly tested. Here we study the impact of forced recruitment of Est2 to telomeres on telomere length in the absence of Ku’s ability to bind TLC1 or DNA ends. We show that tethering Est2 to telomeres does not promote efficient telomere elongation in the absence of Ku–TLC1 interaction or DNA end binding. Moreover, restoration of TLC1 nuclear localization, even when combined with Est2 recruitment, does not bypass the role of Ku. In contrast, forced recruitment of Est1, which has roles in telomerase recruitment and activation, to telomeres promotes efficient and progressive telomere elongation in the absence of Ku–TLC1 interaction, Ku DNA end binding, or Ku altogether. Ku associates with Est1 and Est2 in a TLC1-dependent manner and enhances Est1 recruitment to telomeres independently of Est2. Together, our results unexpectedly demonstrate that the principal role of Ku in telomere length maintenance is to promote the association of Est1 with telomeres, which may in turn allow for efficient recruitment and activation of the telomerase holoenzyme.
A Co-CRISPR Strategy for Efficient Genome Editing inCaenorhabditis elegans
Authors: Kim Heesun , Ishidate Takao , Ghanta Krishna S , Seth Meetu , Conte Darryl , Shirayama Masaki , Mello Craig C
Published: May 2014

Genome editing based on CRISPR (clustered regularly interspaced short palindromic repeats)-associated nuclease (Cas9) has been successfully applied in dozens of diverse plant and animal species, including the nematode Caenorhabditis elegans. The rapid life cycle and easy access to the ovary by micro-injection make C. elegans an ideal organism both for applying CRISPR-Cas9 genome editing technology and for optimizing genome-editing protocols. Here we report efficient and straightforward CRISPR-Cas9 genome-editing methods for C. elegans, including a Co-CRISPR strategy that facilitates detection of genome-editing events. We describe methods for detecting homologous recombination (HR) events, including direct screening methods as well as new selection/counterselection strategies. Our findings reveal a surprisingly high frequency of HR-mediated gene conversion, making it possible to rapidly and precisely edit the C. elegans genome both with and without the use of co-inserted marker genes.
Nodulação e crescimento do feijoeiro em resposta à aplicação de molibdênio e inoculante rizobiano
Authors: Matoso Stella C. G. , Kusdra Jorge F.
Published: May 2014

O feijoeiro (Phaseolus vulgaris) possui a capacidade de se beneficiar da fixação biológica de nitrogênio; entretanto, o sucesso deste processo é influenciado por diversos fatores. O objetivo deste trabalho foi dimensionar a magnitude da contribuição do molibdênio (fontes e doses) e rizóbios (nativos e introduzidos) para nodulação, acúmulo de nitrogênio e crescimento do feijoeiro IPR 139. O experimento foi realizado no ano de 2011 em casa de vegetação, no delineamento inteiramente casualizado em esquema fatorial 2 x 5 x 2 que, nas sementes, corresponde respectivamente à aplicação, de duas fontes (molibdato de sódio e molibdato de amônio) e cinco doses (0, 1, 2, 3 e 4 g kg-1 de sementes) de Mo na presença e ausência de inoculante rizobiano (Rhizobium tropici SEMIA 4088). As variáveis analisadas foram: massas da parte aérea seca, da raiz seca, total da planta seca, dos nódulos secos e média unitária de nódulos secos, número total de nódulos e nitrogênio total da parte aérea. Os resultados indicam o molibdato de amônio como a melhor fonte para elevar a massa de nódulos formados por rizóbios nativos, nas doses entre 2,0 e 3,0 g kg-1 de sementes. A inoculação de R. tropici SEMIA 4088 não se mostrou eficiente para aumentar o crescimento de planta nem, tampouco, a nodulação e a fixação biológica de nitrogênio.
Componentes de produção, produtividade e eficiência da irrigação do feijão-caupi no cerrado de Roraima
Authors: Locatelli Viviana da E. R. , Medeiros Roberto D. de , Smiderle Oscar J. , Albuquerque José de A. A. de , Araújo Wellington F. , Souza Kelly T. S. de
Published: May 2014

Neste trabalho objetivou-se avaliar os componentes de produção, produtividade e eficiência da irrigação do feijão-caupi em lâminas de irrigação no cerrado de Roraima. Conduziu-se o experimento no Campo experimental Água Boa, da Embrapa Roraima, em cultivo sobre palhada sob irrigação por aspersão convencional, de fevereiro a abril e de setembro a novembro de 2012. Foram testadas cinco lâminas de irrigação 30, 60, 90, 120 e 150% da evapotranspiração de referência (ETo) e três cultivares de caupi: BRS Guariba, BRS Novaera e BRS Pajeú. Foram estabelecidas as lâminas com base em frações da ETo diária do tanque classe A. O delineamento foi em blocos casualizados com tratamentos dispostos em faixas e parcelas subdivididas, com cinco repetições. Avaliaram-se o número de vagens por planta, número de grãos por vagem, massa de cem grãos, produtividade de grãos secos e a eficiência do uso da água. Concluiu-se que as variáveis do BRS Pajeú não foram influenciadas pelos tratamentos, os cultivares BRS Guariba e BRS Novaera obtiveram a máxima produtividade de grãos, 1.275,19 e 1.504,98 kg ha-1, com as respectivas lâminas 74,3 e 94,02% da ETo. A máxima eficiência da irrigação foi obtida com a lâmina de 30% da ETo para os três cultivares.
Características produtivas e qualitativas de melão rendilhado adubado com nitrogênio e potássio
Authors: Silva Matheus de C. , Silva Tonny J. A. da , Bonfim-Silva Edna M. , Farias Lorraine do N.
Published: May 2014

O melão é uma das frutas frescas mais exportadas pelo Brasil com crescente área plantada no Estado de Mato Grosso. Em razão de se encontrar associada aos aspectos quantitativos e qualitativos do fruto, a adubação nitrogenada e a potássica são fatores de destaque na produção do meloeiro. Objetivou-se, através deste estudo, avaliar as características produtivas e qualitativas dos frutos de melão rendilhado cultivado em casa de vegetação em função de doses de nitrogênio e potássio. O estudo foi conduzido no período de abril a agosto de 2012 em delineamento experimental de blocos ao acaso, em esquema fatorial 5 x 5, com quatro repetições. As doses de nitrogênio foram de 0; 40, 80, 120 e 160 mg dm-3 e as de potássio corresponderam a 0, 80 160, 240 e 320 mg dm-3. O melão cultivado foi do tipo cantaloupe, híbrido Rafael. As características avaliadas foram produtividade total, espessura da polpa, teor de sólidos solúveis totais e acidez titulável. O nitrogênio promoveu aumento da produtividade e da qualidade dos frutos, de forma linear crescente enquanto as doses de potássio que promoveram os melhores resultados se situaram no intervalo de 240 a 263,4 mg dm-3 influenciando de forma quadrática às variáveis estudadas.
Adubação potássica para o milho cultivado sob palhada de Capim Marandu
Authors: Cruz Simério C. S. , Machado Carla G. , Sena Júnior Darly G. de , Cruz Sihélio J. S.
Published: May 2014

No Brasil, muitos trabalhos referentes à adubação potássica para a cultura do milho apontam para a ausência de resposta a este nutriente mesmo que a maioria dessas pesquisas seja desenvolvida em solos com teores de K de médio a alto; outro aspecto que deve ser levado em consideração é a presença de plantas de cobertura no sistema que podem influenciar a resposta a este nutriente. Objetivou-se avaliar o efeito de doses de K2O associadas à cobertura vegetal do solo com capim Marandu sobre a produtividade do milho e o teor de K no solo. O experimento consistiu de 8 tratamentos estabelecidos em delineamento de blocos casualisados com parcelas subdivididas. Cada dose de K2O (0, 75, 150, 225 kg ha-1) correspondeu a uma parcela sendo as subparcelas formadas pela presença ou ausência de Brachiaria brizantha cv. Marandu. Em solo com baixo teor de K, o milho responde à adubação potássica, independente da presença de palha de capim Marandu. A adubação potássica aplicada em superfície com ou sem palhada, eleva os teores de K do solo mesmo em camadas mais profundas; como planta de cobertura, o capim Marandu aumenta a eficiência da adubação potássica com consequente aumento de produtividade da cultura do milho.
Aspectos de crescimento e produção da mamoneira irrigada com águas salinas e adubação nitrogenada
Authors: Lima Geovani S. de , Nobre Reginaldo G. , Gheyi Hans R. , Soares Lauriane A. dos A. , Lourenço Givanildo da S. , Silva Saulo S. da
Published: May 2014

O trabalho foi desenvolvido objetivando avaliar o crescimento e a produção da mamoneira cv. BRS Energia cultivada em irrigação com água de diferentes níveis salinos e adubada com distintas doses de nitrogênio, em ensaio conduzido em lisímetros de drenagem sob condições de campo no CCTA/UFCG. O delineamento estatístico utilizado foi o de blocos ao acaso, em arranjo fatorial 5 x 4, com três repetições cujos tratamentos constaram de cinco níveis de condutividade elétrica da água - CEa (0,3; 1,2; 2,1; 3,0 e 3,9 dS m-1) e quatro doses de N (70; 100; 130 e 160 mg N kg-1). A irrigação com águas salinas reduziu o crescimento e a produção da mamoneira, observado pela diminuição na altura de planta, diâmetro caulinar, área foliar, fitomassa seca de folhas e de raízes, massa de sementes total e viáveis, sendo a área foliar a variável mais prejudicada. A aplicação de doses crescentes de N proporcionou aumento na área foliar e na fitomassa seca de folhas. Doses de N de até 131 mg N kg-1 promoveram incremento no acúmulo de fitomassa seca de raízes. A mamoneira cv. BRS Energia respondeu à interação entre os fatores apenas para fitomassa seca de caule.
Variabilidade espacial de parâmetros físico-químicas do solo e biofísicos de superfície em cultivo do sorgo
Authors: Bernardi Alberto C. de C. , Rabello Ladislau M. , Inamasu Ricardo Y. , Grego Célia R. , Andrade Ricardo G.
Published: May 2014

O conhecimento da variabilidade espacial das propriedades do solo e das culturas é importante para as tomadas de decisão sobre o manejo agrícola. Objetivou-se, neste trabalho, avaliar a variabilidade espacial de parâmetros químicos e físicos do solo e biofísicos de superfície de área cultivada com sorgo. O estudo foi conduzido em área de 12 ha de um Argissolo Vermelho Amarelo distrófico. A amostragem de solo georreferenciada e a medição da condutividade elétrica do solo foram realizadas antes do plantio do sorgo. As imagens do satélite Landsat 5 foram utilizadas para calcular os parâmetros biofísicos de superfície. Ferramentas de geoestatística foram utilizadas para se determinar e modelar a variabilidade espacial dos atributos em estudo em que os resultados mostraram que a densidade de amostragem adotada foi insuficiente para uma caracterização adequada da variabilidade espacial de parâmetros do solo. Ocorreu dependência espacial de grau, moderada a forte para CE e parâmetros biofísicos da superfície da imagem de satélite com alcances variando de 74,4 a 181,1 m; por outro lado, o sensoriamento remoto orbital também foi útil para o mapeamento da variabilidade espacial da cultura do sorgo e tem grande potencial para aplicação da Agricultura de Precisão.
Variabilidade espacial de propriedades hidrodinâmicas de um Neossolo Regolítico sob pastagem e caatinga
Authors: Oliveira Júnior José A. S. de , Souza Eduardo S. de , Correa Marcelo M. , Lima José R. de S. , Souza Rodolfo M. S. , Silva Filho Luiz A. da
Published: May 2014

As propriedades hidrodinâmicas dos solos de pastagem e de caatinga, são afetadas por diversos fatores, sobretudo associados a aspectos espaciais e temporais relacionados às diferentes características dos sistemas radiculares e das taxas de pisoteio do gado, mas poucos resultados que avaliem o efeito da magnitude dessas fontes de variabilidade sobre as propriedades hidrodinâmicas dos solos têm sido relatados na literatura. Objetivou-se analisar a variabilidade espacial dos parâmetros que descrevem as curvas de retenção (van Genuchten) e da condutividade hidráulica (Brooks & Corey) da água do solo, obtidos com a metodologia denominada "Beerkan", que se baseia em ensaios de infiltração simplificados e nas informações texturais do solo. Para isto foram realizadas medidas de infiltração e coletadas amostras de solo em duas áreas: uma área de pastagem (Brachiaria decumbens) e outra de caatinga. Os resultados mostraram que o uso do solo com pastagem alterou significativamente as propriedades analisadas quando comparadas com as do solo com caatinga, com alterações mais expressivas na densidade do solo e na condutividade hidráulica. A análise geoestatística identificou a existência de dependência espacial de alguns atributos estudados, permitindo o mapeamento das áreas experimentais.