Growing Fast without Colliding: Polylogarithmic Time Step Construction of Geometric Shapes

Building on two recent models of [Almalki and Michail, 2022] and [Gupta et al., 2023], we explore the constructive power of a set of geometric growth processes. The studied processes, by applying a sequence of centralized, parallel, and linear-strength growth operations, can construct shapes from smaller shapes or from a singleton exponentially fast. A technical challenge in growing shapes that fast is the need to avoid collisions caused, for example, when the shape breaks, stretches, or self-intersects. We distinguish two types of growth operations -- one that avoids collisions by preserving cycles and one that achieves the same by breaking them -- and two types of graph models. We study the following types of shape reachability questions in these models. Given a class of initial shapes $\mathcal{I}$ and a class of final shapes $\mathcal{F}$, our objective is to determine whether any (some) shape $S \in \mathcal{F}$ can be reached from any shape $S_0 \in \mathcal{I}$ in a number of time steps which is (poly)logarithmic in the size of $S$. For the reachable classes, we additionally present the respective growth processes. In cycle-preserving growth, we study these problems in basic classes of shapes such as paths, spirals, and trees and reveal the importance of the number of turning points as a parameter. We give both positive and negative results. For cycle-breaking growth, we obtain a strong positive result -- a general growth process that can grow any connected shape from a singleton fast.Comment: 21 pages with 7 figure

Influence of premolar extraction or non-extraction orthodontic therapy on the angular changes of mandibular third molars

Abstract Aim: To compare the angular changes of the third molars relative to the occlusal planeand to the second molar long axis in extraction group and compare these changes with a non extractiongroup.Materials and methods: The study included pre and post treatment panoramic radiographrecords of 90 subjects treated by first premolar extractions and 90 subjects who had been treatedwith non extraction orthodontic therapy (n=90). Two angular variables were measured. Firstly,the angle between the long axis of the third molar and the occlusal plane (M3–OP) and secondly,the angle between the long axis of the third molar and the long axis of the second molar (M3–M2).Data were analyzed by paired and student’s t-test.Result: The analyzed data to assess the changes in the third molar angulation from pretreatmentto post treatment did not vary significantly in both the groups (pdecreased angular values. The M3–OP angular difference was (7.3± 2.45) in extraction group ascompared to (5.85 ± 1.77) in non extraction group. The M3–M2 angular difference of (4.26±3.11) in extraction group and (2.98 ±1.74) in non-extraction group was observedConclusion: Extraction of premolars did not demonstrate considerable changes on the angulationof the third molars. The factors other than premolar extractions may influence the angulationof the third molars.</p

Diagnostic Accuracy of Integrating Ultrasound and Shear Wave Elastography in Assessing Carpal Tunnel Syndrome Severity: a Prospective Observational Study

Ahmed Mohamed El-Maghraby,1 Yassir Edrees Almalki,2 Mohammad Abd Alkhalik Basha,1 Mohamad Gamal Nada,1 Fatma El Ahwany,1 Sharifa Khalid Alduraibi,3 Shaker Hassan S Alshehri,4 Asim S Aldhilan,3 Ziyad A Almushayti,3 Alaa K Alduraibi,3 Mervat Aboualkheir,5 Osama Attia,6 Mona M Amer,7 Ahmed M Abdelkhalik Basha,8 Ibrahim M Eladl1 1Department of Diagnostic Radiology, Faculty of Human Medicine, Zagazig University, Zagazig, 44519, Egypt; 2Division of Radiology, Department of Internal Medicine, Medical College, Najran University, Najran, 61441, Kingdom of Saudi Arabia; 3Department of Radiology, College of Medicine, Qassim University, Buraidah, 52571, Kingdom of Saudi Arabia; 4Department of Orthopedic Surgery, College of Medicine, King Khalid University, Abha, 61421, Kingdom of Saudi Arabia; 5Department of Internal Medicine, College of Medicine, Taibah University, Madinah, 42361 Kingdom of Saudi Arabia; 6Department of Internal Medicine, Faculty of Human Medicine, Zagazig University, Zagazig, 44519, Egypt; 7Department of Neurology, Faculty of Human Medicine, Zagazig University, Zagazig, 44519, Egypt; 8Faculty of General Medicine, Saint Petersburg State University, Egypt Branch, Cairo, 11646, EgyptCorrespondence: Yassir Edrees Almalki, Email [email protected]: Carpal tunnel syndrome (CTS) is a common condition characterized by compression of the median nerve (MN) within the carpal tunnel. Accurate diagnosis and assessment of CTS severity are crucial for appropriate management decisions. This study aimed to investigate the combined diagnostic utility of B-mode ultrasound (US) and shear wave elastography (SWE) for assessing the severity of CTS in comparison to electrodiagnostic tests (EDT).Materials and Methods: This prospective observational study was conducted over 9-month periods at a tertiary care hospital. A total of 48 patients (36 females, 12 males; mean age 44 ± 10.9 years; age range 28– 57 years) with clinically suspected CTS were enrolled. All patients underwent EDT, US, and SWE. Based on the EDT results, CTS cases were categorized into four groups: mild, moderate, severe, and negative. The cross-sectional area (CSA) and elasticity (E) of the MN were measured at the tunnel inlet (CSAu and Eu) and pronator quadratus region (CSAo and Eo). The differences (CSAu-CSAo and Eu-Eo) were calculated. The primary outcomes were the diagnostic performance of CSAu, CSAu-CSAo, Eu, and Eu-Eo in differentiating moderate/severe from mild/negative CTS compared to EDT findings. Secondary outcomes included a correlation of US/SWE parameters with EDT grades and between each other. ANOVA, correlation, regression, and receiver operating characteristic (ROC) curve analyses were performed.Results: CSAu and CSAu–CSAo increased progressively with worsening CTS severity. E measurements were significantly higher in moderate-to-severe CTS compared to mild or negative cases. The combined metric of CSAu-CSAo at a 5 mm threshold exhibited enhanced performance, with a higher sensitivity (83.3%), specificity (100%), and area under the curve (AUC) (0.98), surpassing the results of CSAu when used independently. Similarly, the SWE measurements indicated that Eu-Eo at a 56.1kPa cutoff achieved an AUC of 0.95, with a sensitivity of 93.3% and specificity of 94.4%, outperforming the metrics for Eu when used alone, which had an AUC of 0.93, with identical sensitivity and specificity values (93.3% and 94.4%, respectively).Conclusion: The integration of ultrasound, shear wave elastography, and electrodiagnostic tests provides a comprehensive approach to evaluate anatomical and neurological changes and guide management decisions for CTS.Keywords: carpal tunnel syndrome, median never, ultrasound, shear wave elastograph

Comparison of total endoscopic thyroidectomy with conventional open thyroidectomy for treatment of papillary thyroid cancer

BackgroundRecent advance of endoscopic techniques has allowed surgeons to perform thyroidectomy via an incision placement at hidden places which lead to better cosmetic acceptability compared with conventional open thyroidectomy.AimsThis study was conducted to summarize the current evidence that compare open thyroidectomy with endoscopic ‎thyroidectomy in treatment of papillary thyroid cancer‎.‎Methods An electronic literature review, including PubMed, Google Scholar, and EBSCO that examining randomized trials of endoscopic thyroidectomy (ET), conventional open thyroidectomy (COT), and management of papillary thyroid carcinoma was carried out.Results The review included 8 randomized studies that compare total endoscopic thyroidectomy versus conventional open thyroidectomy in treatment of papillary thyroid cancer. The findings showed endoscopic thyroidectomy had statically significant cosmetic appearance, less amount of blood loss and occurrence of transient hypocalcaemia than conventional open thyroidectomy in form of cosmetic outcome, amount lower blood loss.ConclusionThe current review showed that, ET has a better cosmetic outcome and lower blood loss compared with COT. While COT was associated with significantly low operation time, hospital stay, drainage time, amount of drainage fluid and transient recurrent laryngeal nerve (RLN) palsy

On Geometric Shape Construction via Growth Operations

In this work, we investigate novel algorithmic growth processes. In particular, we propose three growth operations, full doubling, RC doubling and doubling, and explore the algorithmic and structural properties of their resulting processes under a geometric setting. In terms of modeling, our system runs on a 2-dimensional grid and operates in discrete time-steps. The process begins with an initial shape $S_I=S_0$ and, in every time-step $t \geq 1$, by applying (in parallel) one or more growth operations of a specific type to the current shape-instance $S_{t-1}$, generates the next instance $S_t$, always satisfying $|S_t| > |S_{t-1}|$. Our goal is to characterize the classes of shapes that can be constructed in $O(\log n)$ or polylog $n$ time-steps and determine whether a final shape $S_F$ can be constructed from an initial shape $S_I$ using a finite sequence of growth operations of a given type, called a constructor of $S_F$. For full doubling, in which, in every time-step, every node generates a new node in a given direction, we completely characterize the structure of the class of shapes that can be constructed from a given initial shape. For RC doubling, in which complete columns or rows double, our main contribution is a linear-time centralized algorithm that for any pair of shapes $S_I$, $S_F$ decides if $S_F$ can be constructed from $S_I$ and, if the answer is yes, returns an $O(\log n)$-time-step constructor of $S_F$ from $S_I$. For the most general doubling operation, where up to individual nodes can double, we show that some shapes cannot be constructed in sub-linear time-steps and give two universal constructors of any $S_F$ from a singleton $S_I$, which are efficient (i.e., up to polylogarithmic time-steps) for large classes of shapes. Both constructors can be computed by polynomial-time centralized algorithms for any shape $S_F$

On Geometric Shape Construction via Growth Operations

In this work, we investigate novel algorithmic growth processes. In particular, we propose three growth operations, full doubling, RC doubling and doubling, and explore the algorithmic and structural properties of their resulting processes under a geometric setting. In terms of modeling, our system runs on a 2-dimensional grid and operates in discrete time-steps. The process begins with an initial shape $S_I=S_0$ and, in every time-step $t \geq 1$, by applying (in parallel) one or more growth operations of a specific type to the current shape-instance $S_{t-1}$, generates the next instance $S_t$, always satisfying $|S_t| > |S_{t-1}|$. Our goal is to characterize the classes of shapes that can be constructed in $O(\log n)$ or polylog $n$ time-steps and determine whether a final shape $S_F$ can be constructed from an initial shape $S_I$ using a finite sequence of growth operations of a given type, called a constructor of $S_F$. For full doubling, in which, in every time-step, every node generates a new node in a given direction, we completely characterize the structure of the class of shapes that can be constructed from a given initial shape. For RC doubling, in which complete columns or rows double, our main contribution is a linear-time centralized algorithm that for any pair of shapes $S_I$, $S_F$ decides if $S_F$ can be constructed from $S_I$ and, if the answer is yes, returns an $O(\log n)$-time-step constructor of $S_F$ from $S_I$. For the most general doubling operation, where up to individual nodes can double, we show that some shapes cannot be constructed in sub-linear time-steps and give two universal constructors of any $S_F$ from a singleton $S_I$, which are efficient (i.e., up to polylogarithmic time-steps) for large classes of shapes. Both constructors can be computed by polynomial-time centralized algorithms for any shape $S_F$

Level of Sedentary Behavior and Its Associated Factors among Saudi Women Working in Office-Based Jobs in Saudi Arabia

Research in Saudi Arabia has revealed a shocking level of insufficiently physically active adults, particularly women. The risk of sedentary behavior will likely increase as the number of women with office-based jobs increases. The aim of this study is to determine the level of sedentary behavior, and its associated factors, among Saudi women working office-based jobs in the city of Riyadh. A cross-sectional study of 420 Saudi female employees at 8 office-based worksites were measured to determine body mass index and were given a self-administered survey to evaluate their level of physical activity and sedentary behavior. Median sitting time on work days was 690 min per day (interquartile range, IQR 541–870), with nearly half accumulated during work hours, and 575 min per day (IQR 360–780) on non-work days. Predictors of work day sitting time were level of education, number of children, and working in the private sector. Number of children, whether they were single, and whether they lived in a small home were found to predict non-work day sitting time. This study identifies Saudi women in office-based jobs as a high-risk group for sedentary behavior. There is a need to promote physical activity at worksites and reduce prolonged sitting

Comprehensive Knowledge and Preparedness among Dental Community to Confront COVID-19&mdash;A Multicentric Cross-Sectional Study

The healthcare policy changes need to be updated for better management of the COVID-19 outbreak; hence, there is an urgent need to understand the knowledge and preparedness of healthcare workers regarding the infection control COVID-19. Therefore, the present study aims to assess the knowledge and preparedness towards COVID-19 among dentists, undergraduate, and postgraduates in dental universities one year after the COVID-19 outbreak. The multi-centric cross-sectional study was conducted by evaluating 395 structured, pre-coded, and validated questionnaires obtained from sample units comprising full-time dental students (undergraduates, interns, and postgraduates) and dentists who were currently in practice and who were able to comprehend the languages English or Arabic. The first part of the questionnaire included questions related to demographic characteristics. The second part of the survey consisted of questions that address knowledge concerning COVID-19. The third part of the survey addressed questions based on the preparedness to fight against COVID-19 including sharp injuries during this period. Comparing the knowledge scores of dentists, dental undergraduates, and postgraduates using the ANOVA test, dentists have higher knowledge and preparedness scores than postgraduates and undergraduates (p-value &lt; 0.05). Univariate logistic regression analysis demonstrated that undergraduates and postgraduates were 2.567 and 1.352 times less aware of the personal protective measures against COVID-19 than dentists, respectively. Dentists had the comparatively better perception in knowledge and awareness of COVID-19 than undergraduates and postgraduates