Entrepreneurial orientation and firm performance in the context of upper echelon theory.

Entrepreneurial Orientation (EO) is a firm-level phenomenon, which involves the firm’s prospects to take risks, be proactive, and be innovative. Most of the research assumes a positive EO-performance relationship adopting the EO-as-advantage perspective without providing enough theoretical foundations of the way EO enhances performance. This paper provides insights into the EO and firm performance relationship looking into the EO-as-experimentation perspective. Through EO-as-experimentation perspective, we argue for the importance of looking into the differential effects of each of the EO dimensions on firm performance in active and inactive firms. We hypothesized that the effect of each of the proactiveness and innovativeness dimension of EO on firm performance is positive among active firms and negative among inactive firms. Whereas risk taking dimension of EO is negative among active and inactive firms. Based on the results of firm fixed effect regression some empirical support for the hypotheses is presented and discussed

Isolated gallbladder rupture following blunt abdominal trauma

The gallbladder is a relatively well‑protected organ; consequently its rupture following blunt abdominal injury is rare and usually associated with other visceral injuries. Isolated gallbladder rupture is extremely rare. We report a healthy Nigerian adult male who sustained isolated gallbladder rupture following blunt abdominal injury from riding a motor cycle (Okada). A high index of suspicion with positive bile aspirate might lead to early diagnosis. Open cholecystectomy is a safe option of treatment in a resource poor centre especially in delayed presentation and has a good outcome.Key words: Blunt abdominal trauma, gallbladder rupture, isolate

Photo induced ionization dynamics of the nitrogen vacancy defect in diamond investigated by single shot charge state detection

The nitrogen-vacancy centre (NV) has drawn much attention for over a decade, yet detailed knowledge of the photophysics needs to be established. Under typical conditions, the NV can have two stable charge states, negative (NV-) or neutral (NV0), with photo induced interconversion of these two states. Here, we present detailed studies of the ionization dynamics of single NV centres in bulk diamond at room temperature during illumination in dependence of the excitation wavelength and power. We apply a recent method which allows us to directly measure the charge state of a single NV centre, and observe its temporal evolution. Results of this work are the steady state NV- population, which was found to be always < 75% for 450 to 610 nm excitation wavelength, the relative absorption cross-section of NV- for 540 to 610 nm, and the energy of the NV- ground state of 2.6 eV below the conduction band. These results will help to further understand the photo-physics of the NV centre.Comment: 9 pages, 7 figure

Characterization of the nitrogen split interstitial defect in wurtzite aluminum nitride using density functional theory

We carried out Heyd-Scuseria-Ernzerhof hybrid density functional theory plane wave supercell calculations in wurtzite aluminum nitride in order to characterize the geometry, formation energies, transition levels and hyperfine tensors of the nitrogen split interstitial defect. The calculated hyperfine tensors may provide useful fingerprint of this defect for electron paramagnetic resonance measurement.Comment: 5 pages, 3 figure

Outcome of surgery for toxic goitres in maiduguri: A single teaching hospital’s perspective

Background: Thyrotoxicosis a common endocrine disorder of the thyroid gland in Nigeria is commonly treated surgically. The outcome of thyroidectomy for toxic goiters in Maiduguri Nigeria is evaluated.Materials and Methods: Over the last 5 years (Jan 2005-July 2010), in a prospective review, the demographic, and clinical data of patients operated for toxic goiters in our department was entered, into a predesigned proforma and analyzed. The objective of the study is to review our experience with subtotal and near-total thyroidectomy as treatment for benign toxic goiters.Results: Seventy-eight patients, 11 males (14.1%) and 67 females (85.9%), with male: female ratio of 1:6.1 and the mean age of 30 &#177; 10.9 (range, 17-65 years), underwent thyroidectomy for toxic goiters. The mean duration of symptoms was 41.9 (range 3-126 months). There were 53 patients with toxic diffuse goiters (Grave&#8217;s disease) with their mean age of 27.6 &#177; 6.93 (range 17-38 years), 23 with toxic multinodular goiters, the mean age of 43.7 &#177; 15.68 (range 17-65 years) and two with toxic nodule. There was no case of permanent recurrent laryngeal nerve palsy or permanent hypocalcemia. Transient hypocalcemia occurred in 9 (11.5%) patients and hemorrhage with hematoma, requiring exploration in 4 (5.1%). There were two cases of wound infection and no postoperative mortality. The mean hospital stay was 7.6 &#177; 2.34 (range 5-15 days). There was no disease recurrence over a mean follow-up of 20.7 (range 2-48) months.Conclusion: Subtotal thyroidectomy is an effective procedure for the treatment of thyrotoxicosis with few postoperative complications and majority of patients being euthyroid after long follow-up

Single-photon emitting diode in silicon carbide

Electrically driven single-photon emitting devices have immediate applications in quantum cryptography, quantum computation and single-photon metrology. Mature device fabrication protocols and the recent observations of single defect systems with quantum functionalities make silicon carbide (SiC) an ideal material to build such devices. Here, we demonstrate the fabrication of bright single photon emitting diodes. The electrically driven emitters display fully polarized output, superior photon statistics (with a count rate of $>$300 kHz), and stability in both continuous and pulsed modes, all at room temperature. The atomic origin of the single photon source is proposed. These results provide a foundation for the large scale integration of single photon sources into a broad range of applications, such as quantum cryptography or linear optics quantum computing.Comment: Main: 10 pages, 6 figures. Supplementary Information: 6 pages, 6 figure