هدف: بر اساس مطالعه، بسیاری از دانشجویان، سال اول دانشگاه را یکی دوره‌های زمانی پراسترس و چالش‌زای زندگی می‌دانند قادر به سازگاری مناسب با آن نیستند. مطالعه حاضر هدف شناسایی تجارب زیسته دانشجویان پایین در خصوص مشکلات چالش‌های انجام شد. روش: روش پژوهش کیفی نوع پدیدارشناسی بود. داده‌ها استفاده مصاحبه نیمه ساختاریافته جمع‌آوری شد رویکرد 7 مرحله‌ای کلایزی مورد تجزیه تحلیل قرار گرفت. جامعه کلیه آزاد...

Using fractal noise images, we measured the dependence of Dmin and Dmax for stereo on the interocular differences of spatial frequency and contrast. Dmin exhibits a strong dependence on the highest spatial frequency contained in the image, while Dmax exhibits a weaker dependence on the lowest spatial frequency contained within the image. Neither relationship was found to be different when the f...

To quantitatively evaluate dosimetric effects of rotational offsets in stereotactic body radiation therapy (SBRT) for lung cancer. Overall, 11 lung SBRT patients (8 female and 3 male; mean age: 75.0 years) with medially located tumors were included. Treatment plans with simulated rotational offsets of 1°, 3°, and 5° in roll, yaw, and pitch were generated and compared with the original plans. Bo...

In this study, we evaluate dosimetric advantages of using patient-specific aperture system with intensity-modulated proton therapy (IMPT) for head and neck tumors at the shallow depth. We used four types of patient-specific aperture system (PSAS) to irradiate shallow regions less than 4 g/cm2 with a sharp lateral penumbra. Ten head and neck IMPT plans with or without aperture were optimized sep...

A graph G = (V,E) is called a pairwise compatibility graph (PCG) if there exists an edge-weighted tree T and two non-negative real numbers dmin and dmax such that each vertex u ′ ∈ V corresponds to a leaf u of T and there is an edge (u′, v′) ∈ E if and only if dmin ≤ dT (u, v) ≤ dmax in T . Here, dT (u, v) denotes the distance between u and v in T , which is the sum of the weights of the edges ...

In conventional presentations of random-dot kinematograms, two frames of random dots are presented in temporal sequence, separated by a blank inter-stimulus interval, and a coherent offset in spatial position is added to dots in one frame relative to dots in the other frame. Direction discrimination performance is limited temporally to inter-stimulus intervals below about 100 msec (Tmax). Exper...

The effect of the statistical uncertainty, or noise, in inverse treatment planning for intensity modulated radiotherapy (IMRT) based on Monte Carlo dose calculation was studied. Sets of Monte Carlo beamlets were calculated to give uncertainties at Dmax ranging from 0.2% to 4% for a lung tumour plan. The weights of these beamlets were optimized using a previously described procedure based on a s...

The problem of efficiently sampling from a set of (undirected, or directed) graphs with a given degree sequence has many applications. One approach to this problem uses a simple Markov chain, which we call the switch chain, to perform the sampling. The switch chain is known to be rapidly mixing for regular degree sequences, both in the undirected and directed setting. We prove that the switch c...

OBJECTIVE To investigate the morphological and hemodynamic parameters associated with middle cerebral artery (MCA)bifurcation aneurysm rupture. METHODS A retrospective study of 67 consecutive patients was carried out based on 3D digital subtraction angiography data. Morphological and hemodynamic parameters including aneurysm size parameters (dome width, height, and perpendicular height), long...