Measuring The Evolving Internet Ecosystem With Exchange Points

The Internet ecosystem comprising of thousands of Autonomous Systems (ASes) now include Internet eXchange Points (IXPs) as another critical component in the infrastructure. Peering plays a significant part in driving the economic growth of ASes and is contributing to a variety of structural changes in the Internet. IXPs are a primary component of this peering ecosystem and are playing an increasing role not only in the topology evolution of the Internet but also inter-domain path routing. In this dissertation we study and analyze the overall affects of peering and IXP infrastructure on the Internet. We observe IXP peering is enabling a quicker flattening of the Internet topology and leading to over-utilization of popular inter-AS links. Indiscriminate peering at these locations is leading to higher endto-end path latencies for ASes peering at an exchange point, an effect magnified at the most popular worldwide IXPs. We first study the effects of recently discovered IXP links on the inter-AS routes using graph based approaches and find that it points towards the changing and flattening landscape in the evolution of the Internet’s topology. We then study more IXP effects by using measurements to investigate the networks benefits of peering. We propose and implement a measurement framework which identifies default paths through IXPs and compares them with alternate paths isolating the IXP hop. Our system is running and recording default and alternate path latencies and made publicly available. We model the probability of an alternate path performing better than a default path through an IXP iii by identifying the underlying factors influencing the end-to end path latency. Our firstof-its-kind modeling study, which uses a combination of statistical and machine learning approaches, shows that path latencies depend on the popularity of the particular IXP, the size of the provider ASes of the networks peering at common locations and the relative position of the IXP hop along the path. An in-depth comparison of end-to-end path latencies reveal a significant percentage of alternate paths outperforming the default route through an IXP. This characteristic of higher path latencies is magnified in the popular continental exchanges as measured by us in a case study looking at the largest regional IXPs. We continue by studying another effect of peering which has numerous applications in overlay routing, Triangle Inequality Violations (TIVs). These TIVs in the Internet delay space are created due to peering and we compare their essential characteristics with overlay paths such as detour routes. They are identified and analyzed from existing measurement datasets but on a scale not carried out earlier. This implementation exhibits the effectiveness of GPUs in analyzing big data sets while the TIVs studied show that the a set of common inter-AS links create these TIVs. This result provides a new insight about the development of TIVs by analyzing a very large data set using GPGPUs. Overall our work presents numerous insights into the inner workings of the Internet’s peering ecosystem. Our measurements show the effects of exchange points on the evolving Internet and exhibits their importance to Internet routing

Benign metastasizing leiomyoma

Benign metastasizing leiomyoma (BML) is a rare condition, affecting predominantly reproductive-age females with uterine leiomyomata and is most often associated with multiple benign-appearing smooth muscle tumors in lungs. We report herein a case of a 38-year-old woman who presented with multiple uterine fibroids for which hysterectomy was carried out on her. Postoperatively, she developed left-sided pleural effusion. Computed chest tomography (CT) scan revealed multiple nodules in both lungs and pleurae. Histopathology of one of the pleura-based nodules revealed a neoplasm composed of interlacing fascicles of spindle cells with uniform nuclei. The tumor cells were positive for alpha-smooth muscle actin and negative for CD34 immunohistochemical stain

The relationship between C-reactive protein and prognostic factors in chronic obstructive pulmonary disease

BACKGROUND: The purpose of the study was to determine the relationship between high sensitivity C-reactive protein (hs-CRP) levels and prognostic factors in chronic obstructive pulmonary disease. METHODS: We studied 50 stable COPD patients with: spirometry, 6 minute walk distance, body mass index, GOLD stage (spirometric classification) and smoking status. In these patients hs-CRP values were measured and compared with those of 50 healthy controls. Then the serum hs-CRP was subjected to evaluation for any correlation with the predictors of outcomes in COPD subjects. RESULTS: Hs-CRP levels were higher in COPD patients than in controls (4.82 vs. 0.88 mg/L p < 0.01). Correlation was found between hs-CRP and the following variables: FEV(1) (r= −0.813; p < 0.01), 6MWD (r= −0.876; p < 0.01), body mass index (r= −0.710; p < 0.01), GOLD stage (r= 0.797, p < 0.01) and smoking status (r= 0.796; p < 0.01). Using multivariate analysis, FEV(1) and 6MWD showed the strongest negative association with hs-CRP levels. CONCLUSIONS: The circulating levels of the inflammatory marker hs-CRP are significantly elevated in patients with COPD, supporting the view that COPD is in part an inflammatory disorder. Hs-CRP levels in stable COPD patients are best correlated with FEV(1) and 6-minute walk distance (6MWD). This information should be considered when hs-CRP levels are measured in stable COPD patients

IMPLEMENTASI PEMBELAJARAN PPKN MENGGUNAKAN MEDIA E-LEARNING BERBASIS EDMODO DI SMAN 1 GUNUNGSARI

This research uses a qualitative approach with descriptive research type. The aim of this research is to determine the implementation of PPKn learning using Edmodo-based e-learning media at SMAN 1 Gunungsari. The subjects in this research were students. Data collection techniques use interviews, observation and documentation. The results show that the implementation of PPKn learning using Edmodo-based e-learning media was carried out by teachers starting from planning, implementation and evaluation, and the impact provided was able to overcome cheating activities

IMPLEMENTASI PEMBELAJARAN PPKN MENGGUNAKAN MEDIA E-LEARNING BERBASIS EDMODO DI SMAN 1 GUNUNGSARI

This research uses a qualitative approach with descriptive research type. The aim of this research is to determine the implementation of PPKn learning using Edmodo-based e-learning media at SMAN 1 Gunungsari. The subjects in this research were students. Data collection techniques use interviews, observation and documentation. The results show that the implementation of PPKn learning using Edmodo-based e-learning media was carried out by teachers starting from planning, implementation and evaluation, and the impact provided was able to overcome cheating activities

Clinico-bacteriology and risk factors for the diabetic foot infection with multidrug resistant microorganisms

Abstract This study was carried out in diabetic patients with foot ulcer, to determine the bacterial profile of infected ulcer, antibiotic resistance of the isolates and to find out the potential risk factors for infection with multidrug resistance. Gram-negative bacilli were screened for extended spectrum β lactamase (ESBL) production and Staphylococcus aureus were screened for methicillin resistance. In the 60 diabetic foot patients, 37(61.6%) were males and 23(38%) were females. 49(81.6%) had T2DM, whereas only 11(18.3%) patients had T1DM. The presence of sensory neuropathy was observed in 66.6% patients. Bacterial infection was found in 86.6% DFU cases, 40% cases had mixed bacterial infection while 48.5% cases had monomicrobial infections. 23.3% DFU patients had infection by multidrug resistant (MDR) organisms. ESBL producer was found in 45.3% gram-negative isolates. 33 % gram-negative strains were positive for blaCTX-M gene followed by blaSHV (20%) and blaTEM (6.6%) Poor glycemic control in 63.3% patients, duration of infection &gt; 1month (43.3%) and ulcer size &gt; 4cm2 (78.1%) was independently associated with risk of MDR organism infection

Exploring Teachers’ Perceptions of the Barriers to Teaching STEM in High Schools in Qatar

Understanding teachers’ attitudes and perceptions of STEM teaching is a key pathway to enhance effective STEM teaching. Inarguably, teachers are the cornerstone of educational quality and play a central role in students’ academic performance. Specifically, the pedagogical strategies teachers employ and their effective use in the classroom are strong determinants of students’ enrollment or retention in STEM fields of study and eventual careers. This study sought to explore the experiences of high school STEM teachers in Qatar, focusing on the pedagogical approaches they utilize and the challenges they encounter, with the aim of delving into how these approaches and barriers affect the teaching of STEM in the country’s high schools. The study’s design is observational, with data collected using a survey of 299 secondary high school STEM teachers (11th and 12th grades). To attain the goal of this study, we examined the barriers perceived to impede engagement in effective STEM teaching from high school teachers’ perspective. The study’s findings pointed to the influence of student- and school-related factors in shaping STEM teaching. Significant differences were detected based on teachers’ gender, grade level of teaching, age group, and university education. Logistic regressions revealed that teachers’ demographic attributes, including age group and university education, affect their likelihood to use STEM pedagogies in class. This likelihood was significantly affected by student-related barriers and the learning resources/materials employed in classrooms. These findings postulate critical evidence in directing the development of successful STEM learning practices within Qatar’s high schools.The project was funded by Qatar University (Reference: QUCG-SESRI-20/21-1)

Symptomatic surgically treated non-neoplastic cysts of the central nervous system: a clinicopathological study from Pakistan

Objective: To report clinicopathologic features of symptomatic surgically removed non-neoplastic cysts of the central nervous system (CNS). Study Design: Case series. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 2003 to 2012. Methodology: All non-neoplastic CNS cysts reported during the study period were retrieved and reviewed. Age, gender, location, histologic type and clinical features were noted. Results: A total of 124 cysts were diagnosed in the study period. These included 44 epidermoid cysts (mean age 30.5 ± 13.8 years), 35 colloid cysts (mean age 31 ± 13.2 years), 32 arachnoid cysts (mean age 24.8 ± 20.2 years), 6 dermoid cysts, 3 enterogenous cysts and Rathke\u27s cleft cysts each and 1 ependymal cyst. All cyst types mainly presented in young adults in both genders with signs and symptoms of a mass lesion. Conclusion: Non-neoplastic cyst mainly presented like a CNS mass lesion in young adults. Epidermoids were the most common type of these cysts in the present series followed by the colloid and the arachnoid cysts

Central, extraventricular and atypical neurocytomas: a clinicopathologic study of 35 cases from Pakistan plus a detailed review of the published literature

Background: Central neurocytomas are rare neuronal neoplasms with a favorable prognosis. They are typically located in the lateral ventricles of the brain and mostly histologically correspond to WHO grade II with a Mib 1 labelling index of 2 % and are designated as atypical neurocytomas.AIM: The aim of our study was to describe the common as well as unusual morphologic features and the role of various immunohistochemical stains in the diagnosis of these rare tumors.MATERIALS AND Methods: We retrieved and reviewed 35 cases diagnosed between 2001 and 2015.Results: Sixty percent of patients were males, and the mean age was 26 years. 31 cases (88.6%) were intraventricular and 4(11.4%) were extraventricular. Histologically, 6 cases (17.1%) were compatible with atypical neurocytomas . All cases showed the classic morphology comprising nests and sheets of uniform, round cells with uniform round to oval nuclei with finely speckled chromatin and perinuclear cytoplasmic clearing (halos). All cases also showed delicate, fibrillary, neuropil-like matrices. Other common histologic features included capillary-sized blood vessels in a branching pattern in 57.1%, foci of calcification in 34.3% and perivascular pseudorosettes in 20%. Rare findings included Homer- Wright or true rosettes in 8.6% and ganglioid cells in 2.9%. Synaptophysin was the most consistent and valuable marker, being positive in almost all cases. GFAP positivity in tumor cells was seen in 25.7% of cases. Follow up was available in 13 patients. Of these 9 had histologically typical and 4 had atypical tumors. Only 1 (with an atypical neurocytoma) died, probably due to complications of surgery within one month, while 12 (including 3 with atypical neurocytomas) remained alive. Recurrence developed in 1 of these 12 patients (histologically consistent with typical morphology) almost 9 years after surgery. Only 4 patients, including 2 with atypical tumors, received postoperative radiotherapy, all with surgery in 2010 or later. Overall, prognosis was excellent with prolonged, recurrence free survival and most patients, even without receiving radiation therapy, were alive and well for many years, even a decade or more after surgery, without developing any recurrence, indicating the benign nature of these neoplasms

Computational fluid dynamics study of pull and plug flow boundary condition on nasal airflow

The recent advances in the computer based computational fluid dynamics (CFD) software tools in the study of airflow behavior in the nasal cavity have opened an entirely new field of medical research. This numerical modeling method has provided both engineers and medical specialists with a clearer understanding of the physics associated with the flow in the complicated nasal domain. The outcome of any CFD investigation depends on the appropriateness of the boundary conditions applied. Most researchers have employed plug boundary condition as against the pull flow which closely resembles the physiological phenomenon associated with the breathing mechanism. A comparative study on the effect of using the plug and pull flow boundary conditions are evaluated and their effect on the nasal flow are studied. Discretization error estimation using Richardson's extrapolation (RE) method has also been carried out. The study is based on the numerical model obtained from computed tomographic data of a healthy Malaysian subject. A steady state Reynold averaged Navier–Stokes and continuity equations is solved for inspiratory flow having flow rate 20 L/min representing turbulent boundary conditions. Comparative study is made between the pull and plug flow model. Variation in flow patterns and flow features such as resistance, pressure and velocity are presented. At the nasal valve, the resistance for plug flow is 0.664 Pa-min/L and for pull flow the value is 0.304 Pa-min/L. The maximum velocity at the nasal valve is 3.28 m/s for plug flow and 3.57 m/s for pull flow model