Sana'a University (Arabic: جامعة صنعاء) was established in 1970 as the first and the primary university in the Yemen Arab Republic (North Yemen), now the Republic of Yemen (see also Aden University). It is located in Sanaa, the capital of Yemen, and is currently organized with 17 faculties. Previously the university was located at 15°20′53.16″N 44°11′26.83″E / 15.3481000°N 44.1907861°E / 15.3481000; 44.1907861 (Old University).The university includes several accommodation buildings for staff and students and is partnered with the Kuwait University Hospital for medical students.
This study examines how Entrepreneurial Orientation (EO) influences the economic performance (ECONP) of manufacturing SMEs in Yemen, with environmental performance (EP) tested as a mediating factor. Unlike prior research that has largely focused on developed economies, this paper provides new insights into sustainability pathways in resource-constrained and institutionally unstable contexts. Grounded in Contingency Theory and the Resource-Based View, the study employs a quantitative design using a cross-sectional survey of 199 Yemeni manufacturing SMEs. Structural Equation Modeling with Partial Least Squares (PLS-SEM) was applied to test the hypothesized relationships. Results indicate that EO positively affects both EP and ECONP, and that EP partially mediates the EO–ECONP link. This finding underscores the strategic importance of environmental practices for economic resilience in developing-country SMEs. The novelty of this study lies in being the first to empirically test the mediating role of EP in the EO–ECONP relationship within Yemeni SMEs, thereby extending sustainability research to a context that has been largely overlooked. The use of PLS-SEM confirmed the hypothesized relationships, showing EO’s positive effects and EP’s partial mediation, while demonstrating the methodological suitability of this approach for complex, multidimensional sustainability outcomes. Future research should extend this framework to other regions and incorporate social performance dimensions to provide a more comprehensive view of sustainable SME performance.
This study numerically investigates steady boundary-layer flow, melting heat transfer, and bioconvection in a thixotropic nanofluid over a porous stretching surface. The model incorporates a transverse magnetic field, Darcy porous resistance, thermal radiation, heat generation/absorption, and a first-order chemical reaction. Nanoparticle transport is described using Buongiorno’s formulation through Brownian diffusion and thermophoresis, and cross-diffusion effects (Soret and Dufour) are included. Using similarity transformations, the governing partial differential equations are reduced to a coupled set of nonlinear ordinary differential equations, which are solved with MATLAB’s bvp4c solver. The results show that magnetic and porous resistance suppresses the velocity field, while melting enhances near-wall motion. Thermophoresis increases the thermal boundary-layer thickness, whereas stronger melting reduces temperature. Higher Schmidt number and stronger chemical reaction decrease nanoparticle concentration and increasing the bioconvection Lewis number reduces microorganism density. The findings provide parametric guidance for controlling momentum, heat, mass, and microorganism transport in porous-surface coating and thermal processing applications.
Flexible PVDF-based electrolyte films incorporating AgNO3/LiCl nanofillers were prepared via a solution casting process. Hybrid salt additives were introduced at varying concentrations (0.5, 1.5, and 3.0 wt.%) into the PVDF matrix to assess their impact on the structural, optical, and electrical properties of the composite films. XRD analysis confirmed a decrease in crystallinity from 36.32% in pure PVDF to 17.95% at 3.0 wt.% loading, indicating increased amorphous content conducive to ionic mobility. FTIR spectroscopy revealed strong interactions between nanofillers and the polymer, with shifts and broadening of characteristic bands. UV-Vis spectroscopy showed enhanced absorption in the UV-Visible range and a notable decrease in optical bandgaps, from 3.51 eV (direct) in pure PVDF to 2.53 eV in the 3.0 wt.% sample. AC conductivity measurements revealed a significant increase in conductivity with filler content, particularly at high frequencies, attributed to enhanced charge transport via hopping mechanisms. Dielectric analysis showed a marked increase in dielectric constant (up to 7.4 x 104 at 1.5 wt.%) and dielectric loss at low frequencies. Electric modulus and Cole-Cole plots confirmed improved relaxation behavior and reduced bulk resistance. These results demonstrate that PVDF- AgNO3/LiCl nanocomposites are promising candidates for high-performance solid polymer electrolytes in energy storage and optoelectronic applications.
. This article investigates the monotonic properties and oscillatory behavior of quasilinear fourth-order neutral differential equations in the noncanonical case. By establishing new monotonic properties for positive solutions, we derive refined relationships between the solutions and their associated auxiliary functions. Based on these results, effective oscillation criteria are obtained to ensure the oscillation of all solutions. The results are supported by illustrative examples and extend and improve several existing works, and provide a useful approach for studying more general classes of higher-order nonlinear neutral differential equations.
There is conflicting evidence regarding the optimal management strategy for cervical radiculopathy. We conducted a meta-analysis to evaluate the relative effectiveness of nonsurgical treatment and surgical care in adult patients with cervical radiculopathy. We systematically searched PubMed, Embase, and the Cochrane Library to identify randomized controlled trials (RCTs) comparing nonsurgical treatment with surgical treatment. All statistical analyses were performed using RevMan version 5.4. Five RCTs met the inclusion criteria. Surgical treatment significantly improved neck pain (SMD 0.70, 95
