Orientation-dependent binding energy of graphene on palladium

Using density functional theory calculations, we show that the binding strength of a graphene monolayer on Pd(111) can vary between physisorption and chemisorption depending on its orientation. By studying the interfacial charge transfer, we have identified a specific four-atom carbon cluster that is responsible for the local bonding of graphene to Pd(111). The areal density of such clusters varies with the in-plane orientation of graphene, causing the binding energy to change accordingly. Similar investigations can also apply to other metal substrates, and suggests that physical, chemical, and mechanical properties of graphene may be controlled by changing its orientation.Comment: 5 pages, 6 figure

Hydrogen molecule in a magnetic field: The lowest states of the Pi manifold and the global ground state of the parallel configuration

The electronic structure of the hydrogen molecule in a magnetic field is investigated for parallel internuclear and magnetic field axes. The lowest states of the $\Pi$ manifold are studied for spin singlet and triplet$(M_s = -1)$ as well as gerade and ungerade parity for a broad range of field strengths $0 \leq B \leq 100 a.u.$ For both states with gerade parity we observe a monotonous decrease in the dissociation energy with increasing field strength up to $B = 0.1 a.u.$ and metastable states with respect to the dissociation into two H atoms occur for a certain range of field strengths. For both states with ungerade parity we observe a strong increase in the dissociation energy with increasing field strength above some critical field strength $B_c$. As a major result we determine the transition field strengths for the crossings among the lowest $^1\Sigma_g$, $^3\Sigma_u$ and $^3\Pi_u$ states. The global ground state for $B \lesssim 0.18 a.u.$ is the strongly bound $^1\Sigma_g$ state. The crossings of the $^1\Sigma_g$ with the $^3\Sigma_u$ and $^3\Pi_u$ state occur at $B \approx 0.18$ and $B \approx0.39 a.u.$, respectively. The transition between the $^3\Sigma_u$ and $^3\Pi_u$ state occurs at $B \approx 12.3 a.u.$ Therefore, the global ground state of the hydrogen molecule for the parallel configuration is the unbound $^3\Sigma_u$ state for $0.18 \lesssim B \lesssim 12.3 a.u.$ The ground state for $B \gtrsim 12.3 a.u.$ is the strongly bound $^3\Pi_u$ state. This result is of great relevance to the chemistry in the atmospheres of magnetic white dwarfs and neutron stars.Comment: submitted to Physical Review

Self-regulation of time management: mental contrasting with implementation intentions

Mental contrasting with implementation intentions (MCII) has been found to improve self-regulation across many life domains. The present research investigates whether MCII can benefit time management. In Study 1, we asked students to apply MCII to a pressing academic problem and assessed how they scheduled their time for the upcoming week. MCII participants scheduled more time than control participants who in their thoughts either reflected on similar contents using different cognitive procedures (content-control group) or applied the same cognitive procedures on different contents (format-control group). In Study 2, students were taught MCII as a metacognitive strategy to be used on any upcoming concerns of the subsequent week. As compared with the week prior to the training, students in the MCII (vs. format control) condition improved in self-reported time management. In Study 3, MCII (vs. format control) helped working mothers who enrolled in a vocational business program to attend classes more regularly. The findings suggest that performing MCII on one's everyday concerns improves time management

Contacting single bundles of carbon nanotubes with alternating electric fields

Single bundles of carbon nanotubes have been selectively deposited from suspensions onto sub-micron electrodes with alternating electric fields. We explore the resulting contacts using several solvents and delineate the differences between Au and Ag as electrode materials. Alignment of the bundles between electrodes occurs at frequencies above 1 kHz. Control over the number of trapped bundles is achieved by choosing an electrode material which interacts strongly with the chemical functional groups of the carbon nanotubes, with superior contacts being formed with Ag electrodes.Comment: 4 pages, RevTe

Identification of a novel retroviral gene unique to human immunodeficiency virus type 2 and simian immunodeficiency virus SIVMAC

Human and simian immunodeficiency-associated retroviruses are extraordinarily complex, containing at least five genes, tat, art, sor, R, and 3' orf, in addition to the structural genes gag, pol, and env. Recently, nucleotide sequence analysis of human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus SIVMAC revealed the existence of still another open reading frame, termed X, which is highly conserved between these two viruses but absent from HIV-1. In this report, we demonstrate for the first time that the X open reading frame represents a functional retroviral gene in both HIV-2 and SIVMAC and that it encodes a virion-associated protein of 14 and 12 kilodaltons, respectively. We also describe the production of recombinant TrpE/X fusion proteins in Escherichia coli and show that sera from some HIV-2-infected individuals specifically recognize these proteins

Improved asymmetry prediction for short interfering RNA s

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102096/1/febs12599.pd

Eficiência agronômica de tecnologias de tratamento da ureia na cultura do algodão.

A cultura do algodão utiliza grande quantidade de fertilizantes nitrogenadas no processo produtivo. O objetivo deste trabalho foi avaliar tecnologias de tratamento da ureia para aumento da sua eficiência, no algodão. Avaliou-se o efeito de cinco fertilizantes nitrogenados em três doses, sob delineamento fatorial, além de um tratamento controle sem adubação nitrogenada, em duas safras no Mato Grosso, no rendimento de algodão em caroço, no número de maças, no peso de capulhos, na altura final e população de plantas. As doses de N avaliadas foram 0, 60, 90 e 120 kg ha-1, correspondentes à 0, 50, 75 e 100% da dose recomendada, respectivamente. Os parâmetros avaliados foram alterados positivamente pelas doses, mas não pelas tecnologias de tratamento da ureia, em ambas as safras. As tecnologias de tratamento para aumento da eficiência da ureia não permitem reduzir a dose de N recomendada, mas aumenta a eficiência agronômica na dose recomendada, em comparação com a ureia comum