Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Heat transfer. The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Low-temperature plasma probe for ambient desorption ionization.

Abstract: A low-temperature plasma (LTP) probe has been developed for ambient desorption ionization. An ac electric field is used to induce a dielectric barrier discharge through use of a specially designed electrode configuration. The low-temperature plasma is extracted from the probe where it interacts directly with the sample being analyzed, desorbing and ionizing surface molecules in the ambient environment. This allows experiments to be performed without damage to the sample or underlying substrate and, in the case of biological analysis on skin surfaces, without electrical shock or perceptible heating. Positive or negative ions are produced from a wide range of chemical compounds in the pure state and as mixtures in the gaseous, solution, or condensed phases, using He, Ar, N2, or ambient air as the discharge gas. Limited fragmentation occurs, although it is greater in the cases of the molecular than the atomic discharge gases. The effectiveness of the LTP probe has been demonstrated by recording characteristi...

The 3.8 Å resolution cryo-EM structure of Zika virus

Abstract: The recent rapid spread of Zika virus and its unexpected linkage to birth defects and an autoimmune-neurological syndrome has generated worldwide concern Zika virus is a flavivirus like dengue, yellow fever and West Nile viruses We present the 38A resolution structure of mature Zika virus determined by cryo-electron microscopy The structure of Zika virus is similar to other known flavivirus structures except for the ~10 amino acids that surround the Asn154 glycosylation site found in each of the 180 envelope glycoproteins that make up the icosahedral shell The carbohydrate moiety associated with this residue, recognizable in the cryo-EM electron density, may function as an attachment site of the virus to host cells This region varies not only among Zika virus strains but also in other flaviviruses and suggests that changes in this region influence virus transmission and disease

Aging and Cumulative Inequality: How Does Inequality Get Under the Skin?

Abstract: Purpose: This article draws from cumulative disadvantage and life course theories to develop a new theory for the social scientific study of aging. Design and Methods: Five axioms of cumulative inequality (CI) theory are articulated to identify how life course trajectories are influenced by early and accumulated inequalities but can be modified by available resources, perceived trajectories, and human agency. Results: Although the concept of CI has attracted considerable attention among social scientists, it holds promise for integrating additional disciplinary approaches to the study of aging including, but not limited to, biology, epidemiology, and immunology. The applicability of CI theory to gerontology is illustrated in research on the early origins of adult health. Implications: Primary contributions of the theory to gerontology include greater attention to family lineage as a source of inequality; genes, gestation, and childhood as critical to early and enduring inequalities; the onset, duration, and magnitude of exposures to risk and opportunity; and constraints on generalizations arising from cohort-centric studies.

Goals and Strategies of a Problem-based Learning Facilitator

Abstract: This paper describes an analysis of facilitation of a student-centered problem-based learning group. The focus of this analysis was to understand the goals and strategies of an expert facilitator in support of collaborative learning. This was accomplished through interaction analysis using video data and stimulated recall to examine two PBL group meetings. In this paper, we examine how specific strategies were used to support the PBL goals of help ing students construct causal explanations, reason effectively, and become self-directed learners while maintaining a student-centered learning process. Being able to articulate these strategies is an important step in helping others learn the art of PBL facilitation.

Deepfake Video Detection Using Recurrent Neural Networks

Abstract: In recent months a machine learning based free software tool has made it easy to create believable face swaps in videos that leaves few traces of manipulation, in what are known as "deepfake" videos. Scenarios where these realistic fake videos are used to create political distress, blackmail someone or fake terrorism events are easily envisioned. This paper proposes a temporal-aware pipeline to automatically detect deepfake videos. Our system uses a convolutional neural network (CNN) to extract frame-level features. These features are then used to train a recurrent neural network (RNN) that learns to classify if a video has been subject to manipulation or not. We evaluate our method against a large set of deepfake videos collected from multiple video websites. We show how our system can achieve competitive results in this task while using a simple architecture.