Real-Time Anomaly Detection in Edge Streams

Given a stream of graph edges from a dynamic graph, how can we assign anomaly scores to edges in an online manner, for the purpose of detecting unusual behavior, using constant time and memory? Existing approaches aim to detect individually surprising edges. In this work, we propose Midas , which focuses on detecting microcluster anomalies , or suddenly arriving groups of suspiciously similar edges, such as lockstep behavior, including denial of service attacks in network traffic data. We further propose Midas -F, to solve the problem by which anomalies are incorporated into the algorithm’s internal states, creating a “poisoning” effect that can allow future anomalies to slip through undetected. Midas -F introduces two modifications: (1) we modify the anomaly scoring function, aiming to reduce the “poisoning” effect of newly arriving edges; (2) we introduce a conditional merge step, which updates the algorithm’s data structures after each time tick, but only if the anomaly score is below a threshold value, also to reduce the “poisoning” effect. Experiments show that Midas -F has significantly higher accuracy than Midas . In general, the algorithms proposed in this work have the following properties: (a) they detects microcluster anomalies while providing theoretical guarantees about the false positive probability; (b) they are online, thus processing each edge in constant time and constant memory, and also processes the data orders-of-magnitude faster than state-of-the-art approaches; and (c) they provides up to 62% higher area under the receiver operating characteristic curve than state-of-the-art approaches.

Mature ovarian teratoma-associated encephalitis

Introduction. Autoimmune encephalitis associated with ovarian teratoma is a serious and potentially fatal pathology. While this clinical entity is known to neurologists, the available literature rarely mentions the role of a gynecologist in diagnostic imagining and treatment. Although several months have passed from the appearance of the symptoms to surgical treatment, this case shows that even then a complete recovery is possible. Case presentation. The patient was a 28-year-old female, brought to the hospital because a sudden onset of unusual behavior - an acute psychosis with suicidal thoughts and auditory hallucinations. Soon after the admission she became delirious, uncooperative and agitated. Blood check, neurological assessment and cranial computed tomography yielded normal results. Therefore, a psychiatric disorder was suspected. Electroencephalogram revealed a diffuse encephalitic insufficiency. As cerebrospinal fluid was negative for infections, the autoimmune etiology of the disease was suspected. Abdominal computer tomography showed a complex right ovarian mass measuring 50 x 40 x 30 mm, confirmed by vaginal ultrasound. Laparoscopy with right adnexectomy was performed. The pathohistological finding showed a mature teratoma. In the meantime, the result of the cerebrospinal fluid test came positive for anti NMDAR antibodies. Six months after surgery, the patient was in a good mental and neurological status without symptoms. Conclusion. Gynecologists should be aware of the presence of ovarian tumors in encephalitis cases. A timely diagnosis of the underlying gynecological cause of a neurological condition, allows for prompt treatment and can remarkably improve clinical conditions and, thus, be lifesaving.

Employing opposite ratings users in a new approach to collaborative filtering

Over the past few decades, various recommendation system paradigms have been developed for both research and industrial purposes to satisfy the needs and preferences of users when they deal with enormous data. The collaborative filtering (CF) is one of the most popular recommendation techniques, although it is still immature and suffers from some difficulties such asparsity, gray sheep and scalability impeding recommendation quality. Therefore, we propose a new CF approach to deal with the gray sheep problem in order to improve the predictions accuracy. To realize this goal, our solution aims to infer new users from real ones existing in datasets. This transformation allows for creating users with opposite preferences to the real ones. On the one hand, our approach permits to amplify the number of neighbors, especially in the case of users who have unusual behavior (gray sheep). On the other hand, it facilitates building a dense similar neighborhood. The basic assumption behind this is that if user X is not similar to user Y, then the imaginary user ¬X is similar to the user Y. The performance of our approach was evaluated using two datasets, MovieLens and FilmTrust. Experimental results have shown that our approach surpasses many traditional recommendation approaches.

Case report on fatal human rabies infection in central India

Rabies is a zoonotic disease that affects the central nervous system of mammals and has a high mortality rate. It is a viral disease that can be prevented by vaccination. Dogs are the leading cause of human rabies deaths, accounting for up to 99% of all human rabies transmissions. On 15th December 2019 an 8 years old male child was bitten by a stray dog outside of his house. The patient visited with his parents to a nearby primary health care center on same day where his wound was washed with water. He received first dose of anti-rabies vaccine and was referred to a tertiary care center for immunoglobulin because of a history of wound bleeding. They did not visit tertiary care center for immunoglobulin as advised. 15 days after exposure on 1st January 2021 the patient presented with unusual behavior like fear of water and tremor. On examination his pupils were found dilated and he was referred to isolation ward of tertiary care center. Based on the history of animal bites and clinical signs, the patient was diagnosed as probable case of rabies. The patient eventually died within 24 hours of admission. Such kind of incident shows that there is lack of awareness regarding rabies in community. In this case, if the patient had completed the anti-rabies vaccination schedule and visited a higher centre on time for immunoglobulin, death could have been avoided. Mortality due to rabies can be prevented by raising public awareness about immunization.

Some properties of energies in nonsynchronous reference frames in cosmology

It is shown that use of non synchronous reference frame in cosmology can lead to unusual behavior of the energy of particles: it can have not only positive but also negative and zero energies. A special example of the model with the scale factor a(t) ∼ t is considered.

Suprasellar Melanocytoma with Leptomeningeal Seeding: An Aggressive Clinical Course for a Histologically Benign Tumor

Introduction. Meningeal melanocytoma (MM) is a very rare neuroectodermal neoplasm arising from the leptomeninges. Primary suprasellar melanocytomas are exceedingly rare, with only a handful of cases reported. The systemic spread of a nontransformed meningeal melanocytoma is an unusual occurrence. Herein, we report the first case of a primary sellar melanocytoma with cerebral and spinal meningeal seeding. Case Report. A 30-year-old male with no previous medical history presented to the endocrinology department with a loss of body hair. The endocrine workup concluded with isolated hypogonadotropic hypogonadism. The Magnetic Resonance Imaging (MRI) of the brain and sella revealed a large suprasellar mass continuous with the infundibulum of the pituitary gland. It was heterogeneously hyperintense on T1-, T2-, and FLAIR-weighted images and was enhanced with contrast, along with cerebral and spinal leptomeningeal spread. The patient was referred to the neurosurgery department, and a lumbar spine biopsy was indicated. The histopathological examination was suggestive of a grade I meningeal pigmented melanocytoma. Conclusion. Thus, primary sellar melanocytomas with leptomeningeal spread are an extremely rare phenomenon. Metastatic malignant melanoma should be ruled out. Being aware of differential diagnosis and the unusual behavior of meningeal melanocytoma will be necessary to manage the patient appropriately. Complete tumor resection is the best treatment whenever possible, and radiotherapy should be considered in case of unresectability or partial resection.

Peculiarities of Aluminum Anodization in AHAs-Based Electrolytes: Case Study of the Anodization in Glycolic Acid Solution

The anodization of aluminum (Al) in three alpha-hydroxy acids (AHAs): glycolic (GC), malic (MC), and citric (CC), was analyzed. Highly ordered pores in GC were obtained for the first time. However, the hexagonal cells were characterized by a non-uniform size distribution. Although common features of current density behavior are visible, the anodization in AHAs demonstrates some peculiarities. The electric conductivity (σ) of 0.5 M GC, MC, and CC electrolytes was in the following order: σ(CC) > σ(MC) > σ(GC), in accordance with the acid strength pKa(CC) < pKa(MC) < pKa(GC). However, the anodization voltage, under which a self-organized pore formation in anodic alumina (AAO) was observed (Umax), decreased with increasing pKa: Umax(CC) > Umax(MC) ≥ Umax(GC). This unusual behavior is most probably linked with the facility of acid ions to complex Al and the active participation of the Al complexes in the AAO formation. Depending on the AHA, its tendency and different modes to coordinate Al ions, the contribution of stable Al complexes to the AAO growth is different. It can be concluded that the structure of Al complexes, their molecular mass, and the ability to lose electrons play more important roles in the AAO formation than pKa values of AHAs.

Self-Propelled Aero-GaN Based Liquid Marbles Exhibiting Pulsed Rotation on the Water Surface

We report on self-propelled rotating liquid marbles fabricated using droplets of alcoholic solution encapsulated in hollow microtetrapods of GaN with hydrophilic free ends of their arms and hydrophobic lateral walls. Apart from stationary rotation, elongated-spheroid-like liquid marbles were found, for the first time, to exhibit pulsed rotation on water surfaces characterized by a threshold speed of rotation, which increased with the weight of the liquid marble while the frequency of pulses proved to decrease. To throw light upon the unusual behavior of the developed self-propelled liquid marbles, we propose a model which takes into account skimming of the liquid marbles over the water surface similar to that inherent to flying water lily beetle and the so-called helicopter effect, causing a liquid marble to rise above the level of the water surface when rotating.

Insights about CO Gas-Sensing Mechanism with NiO-Based Gas Sensors—The Influence of Humidity

Polycrystalline NiO thick film-based gas sensors have been exposed to different test gas atmospheres at 250 °C and measured via simultaneous electrical resistance and work function investigations. Accordingly, we decoupled different features manifested toward the potential changes, i.e., work function, band-bending, and electron affinity. The experimental results have shown that the presence of moisture induces an unusual behavior toward carbon monoxide (CO) detection by considering different surface adsorption sites. On this basis, we derived an appropriate detection mechanism capable of explaining the lack of moisture influence over the CO detection with NiO-sensitive materials. As such, CO might have both chemical and dipolar interactions with pre-adsorbed or lattice oxygen species, thus canceling out the effect of moisture. Additionally, morphology, structure, and surface chemistry were addressed, and the results have been linked to the sensing properties envisaging the role played by the porous quasispherical–hollow structures and surface hydration.

The Potential Treatment of Guava Leaf (Psidium guajava Linn.) For Diarrhea in Children

Diarrhea is one of the common health problems which is causes death in children especially in a developed country. Not everybody can access the diarrhea treatment suggested by WHO. Some people decided to utilize alternative treatment, such as the medicinal plant in their environment. It is cheaper and easier to get. One of herb plant that uses is guava leaf (Psiidium guajava Linn.). It contains some active ingredients such as quercetin, tannins, flavonoids, and phenols which have the potential to antidiarrheal activity. To date no death or unusual behavior reported. Guava leaf (Psiidium guajava Linn.) extract can be provided as potential antidiarrheal in children.