RESUMO
It is demonstrated that the nearest-neighbor Mn pair on the GaAs (001) surface has a lower energy for the [110] direction compared to the [110] case. According to the group theory and Luttinger's method of invariants, this specific Mn distribution results in bulk uniaxial in-plane and out-of-plane anisotropies. The sign and magnitude of the corresponding anisotropy energies determined by a perturbation method and ab initio computations are consistent with experimental results.
Assuntos
Pesquisa em Enfermagem Clínica/métodos , Editoração , Redação , Indexação e Redação de Resumos , Coleta de Amostras Sanguíneas/métodos , Coleta de Amostras Sanguíneas/enfermagem , Cateteres de Demora , Enfermagem em Emergência/métodos , Medicina Baseada em Evidências , Hematócrito , HumanosRESUMO
BACKGROUND: Most trauma patients in the emergency department have multiple hematocrits drawn to monitor hypovolemia. These venipunctures are painful to the patient and frustrating for hospital staff when venipuncture sites are difficult to locate. PURPOSE: The purpose of this study was to determine whether the hematocrit values of blood samples obtained with saline lock devices agree or are different from those blood specimens obtained by standard venipuncture. If they agree, can the traditional venipuncture route of blood collection be replaced by collection from a saline lock device? METHODS: The study used a quasiexperimental, repeated measures design. The research was conducted at a teaching, regional level I trauma center with annual ED visits of 65,000. Each subject had hematocrit samples obtained by venipuncture (control) according to standard trauma protocols. Within 5 minutes of obtaining each control specimen, a hematocrit sample was obtained with a saline lock device (experimental) after a 5 ml discard volume was obtained. RESULTS: Results were analyzed by measures of central tendency and paired t test. There were no differences in mean hematocrit values in blood obtained by saline locks (41.1 +/- 4.4) and those drawn from direct venipunctures (41.0 +/- 3.9). CONCLUSIONS: Obtaining samples for determination of hematocrit values from a saline look device is an accurate method of obtaining serial hematocrit values.