The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission

Numerical calculations based on the recursive Green's functions method in the tight-binding approximation are performed to calculate the dimensionless conductance $g$ in disordered graphene nanoribbons with Gaussian scatterers. The influence of the transition from short- to long-ranged disorder on $g$ is studied as well as its effects on the formation of a perfectly conducting channel. We also investigate the dependence of electronic energy on the perfectly conducting channel. We propose and calculate a backscattering estimative in order to establish the connection between the perfectly conducting channel (with $g=1$) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.

School psychology in Portugal: practitioners’ characteristics and practices

Little empirical evidence is available on the professional characteristics and practices of school psychologists in Portugal. This study surveyed a total of 477 Portuguese school psychologists employed in public (80%) and private schools (20%). Portuguese school psychologists are described with regard to demographic, professional, and educational backgrounds, school settings, roles performed, and main target populations served. Evaluating and counseling regular education students, vocational guidance, and special education-related activities emerged as the most time-consuming professional practices. A professional practice primarily focused on students, mainly from the highest education levels, was also observed. Results are compared with findings of previous surveys and reviewed in the context of the current literature on the school psychologist’s role. Implications for the field are also provided.Department of Educational Psychology and Special Education, University of Minho, Braga, PortugalSchool Psychology Program, School of Education, University of North Carolina, Chapel Hill, North Carolina, US

Mutagenicity of New Lead Compounds to Treat Sickle Cell Disease Symptoms in a Salmonella/Microsome Assay

A series of phthalimide derivatives planned as drugs candidates to treat the symptoms of sickle cell anemia were evaluated in a mutagenicity test using strains of Salmonella typhimurium TA100 and TA102, without and with addition of S9 mixture, with the aim to identify the best structural requirements for a drug candidate without genotoxic activity. The compounds (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl nitrate (1); (1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)ethyl nitrate (2); 3-(1,3-dioxo-1,3-dihydro-2H-iso-indol-2-yl)benzyl nitrate (3); 4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-N-hydroxy-benzenesulfonamide (4); 4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)benzyl nitrate (5) and 2-[4-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)phenyl]ethyl nitrate (6) presented mutagenic potency ranging between 0–4,803 revertants/μmol. These results allowed us to propose that a methyl spacer linked to a nitrate ester subunit associated to meta aromatic substitution decreases mutagenicity

Serum markers of B-cell activation in pregnancy during late gestation, delivery, and the postpartum period

B cells are vital for the normal evolution of pregnancy due to their humoral and possible regulatory activities. Our group and others have documented that circulating B-cell subsets undergo changes from normal late pregnancy to the postpartum period. However, the underlying mechanisms are poorly understood. Therefore, this study examined the degree of B-cell activation in normal pregnancy by analyzing the levels of serum markers in healthy pregnant women during the third trimester of pregnancy, the day of delivery, and the postpartum period. METHOD OF STUDY: A prospective study including pregnant and non-pregnant women attending routine care was undertaken at a hospital clinic. Sociodemographic and clinical data were collected, along with peripheral blood samples. The serum levels of soluble CD23 (sCD23), B-cell-activating factor (BAFF), kappa (κ) and lambda (λ) free light chains (FLC), IgA, IgG, and IgM were quantified. RESULTS: Our study included 43 third trimester pregnant and 35 non-pregnant women. In the pregnant women, the median levels of sCD23, BAFF, IgG, and κ FLC were significantly higher during the postpartum period than during the third trimester of pregnancy. Compared to the non-pregnant women, the third trimester pregnant women had higher median BAFF levels and lower sCD23, IgA, IgG, and FLC levels. CONCLUSION: Changes in serum markers of B-cell kinetics that occur during pregnancy often persist into the postpartum period and affect the secretion of immunoglobulins from different classes. Further studies are needed to clarify the biological significance of our observations.info:eu-repo/semantics/publishedVersio

Volatilização da amônia da ureia estabilizada com NBPT na adubação em cobertura da Urochloa ruziziensis.

A ureia é o principal adubo nitrogenado utilizado em pastagens. Nesse fertilizante, uma das principais perdas de nitrogênio (N) está relacionada com a volatilização da amônia. O uso de produtos que proporcionam redução das perdas de N da ureia pode contribuir para aumentar a eficiência de uso desse nutriente em pastagens. Assim, objetivou-se determinar o efeito de fontes e doses de N aplicado parcelado em cobertura na Urochloa ruziziensis, nas perdas de N pela volatilização de amônia (N-NH3). O experimento foi conduzido em Santo Antônio de Goiás, GO, em Latossolo Vermelho Distrófico. Utilizou o delineamento experimental de blocos ao acaso, com quatro repetições em arranjo fatorial 2 x 5 x 5. Os tratamentos foram compostos pelas fontes de N: ureia comum e ureia com inibidor de urease, doses de N: 0, 50, 100, 200 e 300 kg ha-1 (parceladas em 5 aplicações) e cinco períodos de crescimento da forrageira: 14/11 a 13/12 (1º período), 14/12 a 12/01 (2º período), 13/01 a 11/02 (3º período), 24/03 a 22/04 (4º período), e 10/07 a 08/08 (5º período). O uso de ureia com inibidor de urease proporcionou reduções nas perdas de amônia por volatilização em relação à ureia comum. O aumento das doses de N proporcionou aumento da volatilização de N-NH3. Ocorreram maiores perdas de N pela volatilização da amônia nos períodos mais secos do ano

A study of the ethical dilemmas experienced by school psychologists in Portugal

Published online: 06 Apr 2015This study examines the ethical dilemmas and difficulties encountered by Portuguese school psychologists. As part of a larger survey, participants were asked about ethical issues faced in daily practice and asked to describe ethical incidents. Of the 477 respondents, 274 reported 441 ethically troubling or challenging situations. Responses were coded into a six-category system based on the code of ethics of Portuguese psychologists. Most of the reported dilemmas concerned privacy and confidentiality principles (53%). Results are discussed in light of relevant literature and international findings. Implications for the development of the profession and future research are provided.This research was financially sponsored by the Portuguese Foundation for Science and Technology (Doctoral grant, SFRH/BD/78646/2011)

Sacrificial Adhesive Bonding: A Powerful Method For Fabrication Of Glass Microchips

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A new protocol for fabrication of glass microchips is addressed in this research paper. Initially, the method involves the use of an uncured SU-8 intermediate to seal two glass slides irreversibly as in conventional adhesive bonding-based approaches. Subsequently, an additional step removes the adhesive layer from the channels. This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests. Named sacrificial adhesive layer (SAB), the protocol meets the requirements of an ideal microfabrication technique such as throughput, relatively low cost, feasibility for ultra largescale integration (ULSI), and high adhesion strength, supporting pressures on the order of 5 MPa. Furthermore, SAB eliminates the use of high temperature, pressure, or potential, enabling the deposition of thin films for electrical or electrochemical experiments. Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature. Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.5Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2010/08559-9]CNPq [482696/2011-7

Adsorptive potential of Zn–Al and Mg–Fe layered double hydroxides for the removal of 2–nitrophenol from aqueous solutions

Two layered double hydroxides (LDH) of the type Zn–Al and Mg–Fe were synthesized, characterized and used as adsorbents to uptake 2–nitrophenol (2–NP) from aqueous solutions. XRD, FTIR, SEM, EDS, AFM and N2 adsorption/desorption curves were used to characterize the Zn–Al–LDH and Mg–Fe–LDH. The potential of both layered double hydroxides to adsorb 2–NP was investigated by adsorption kinetics, equilibrium, thermodynamics and consecutive adsorption/desorption cycles. The characterization indicated a high crystallinity degree and a well–organized and lamellar structure, confirming the efficiency of the synthesis. Elovich was the better kinetic model to describe the 2–NP adsorption onto Zn–Al–LDH, while Pseudo–second order was the best for Mg–Fe–LDH. For both LDHs, the adsorption equilibrium followed the Freundlich model. The process was endothermic, being the maximum adsorption capacities of 290 and 165 mg g–1 for Zn–Al–LDH and Mg–Fe–LDH, respectively. LDHs can be applied for five adsorption/desorption cycles with excellent adsorption capacities. It can be concluded that Zn–Al–LDH and Mg–Fe–LDH are promising materials to treat waters and wastewaters containing 2–nitropheno