Pulse rise time and amplitude detector Patent

Development and characteristics of electric circuitry for detecting electrical pulses rise time and amplitud

Pulse Amplitude and Width Detector-Patent

Electrical testing apparatus for detecting amplitude and width of transient puls

Age and Growth of Predatory Mesopelagic Fishes in a Low-Latitude Oceanic Ecosystem

Mesopelagic and bathypelagic fishes provide important global ecosystem services, such as carbon sequestration via the biological pump and provision of food for economically important (billfishes and tuna) and federally protected (cetaceans and seabirds) species. These attributes are becoming increasingly recognized, while simultaneously mesopelagic fisheries are becoming of interest for direct harvest as coastal fisheries have become overexploited. Additionally, climate change, ocean acidification, and seabed mining threaten deep-sea fishes. With increasing interest in deep-sea fisheries and anthropogenic threats, age and growth information on these fishes is necessary for management and conservation. Currently ecosystem models lack data such as sexual maturity and lifespan on deep-pelagic fishes, hindering our ability to quantify production rates and resilience to disturbance. Here we examine four numerically dominant predatory fishes from the Gulf of Mexico exhibiting a range of trophic ecologies and vertical distributions: Lampanyctus lineatus (Myctophidae), Omosudis lowii (Omosudidae), Stomias affinis (Stomiidae), and Chauliodus sloani (Stomiidae). In this thesis, the otoliths (‘ear stones’) of each species were examined in order to estimate age and duration of specific life history stages (e.g. juvenile, intermediate, and adult) and landmarks (e.g., sexual maturity and determine longevity). Given that otolith ring validation was not possible (these fishes cannot be kept alive, marked and recaptured, and hourly sampling is not possible for species living at great depths), we present putative minimum and maximum estimates at landmarks based on two scenarios: 1) total rings = days of life; and 2) major (darkest) otolith increments = years of life). Comparing both estimates to available validated ages of their prey, we conclude that the maximum age scenario is most appropriate. Results of this study suggest that the deep-living myctophid species and higher-level predators investigated have relatively long generation times (L. lineatus one year, C. sloani 9 - 17 years, and S. affinis 10 – 19 years until sexual maturity), and thus likely have low resilience to population level-perturbation

Evaluation of Nitrous Oxide Emissions from Furrow-irrigated Rice on a Silt-loam Soil in Arkansas

As the number one rice (Oryza sativa)-producing state in the United States, Arkansas also ranks fourth as the largest user of groundwater. Recently, due to the development of drought- resistant hybrid cultivars, the furrow-irrigated rice production system has become an increasingly popular alternative to traditional flood-irrigated production with respect to conserving groundwater and maintaining yield. However, other environmental parameters, like greenhouse gas emissions, specifically nitrous oxide (N2O), have yet to be evaluated under furrow-irrigated rice. The objectives of this study were to i) evaluate the effects of site position (i.e., up-, mid-, and down-slope) and tillage treatment [i.e., conventional tillage (CT) and no-tillage NT)] on N2O fluxes and season-long emissions from a furrow-irrigated rice production system on a silt-loam soil in east-central Arkansas, and ii) to evaluate the effects of nitrogen (N)-fertilization amount and timing [i.e., 100% of the early season optimum N rate plus one split application (OPOS), 50% of the early season optimum N rate plus two split applications (HOPTS), 100% of the early season plus two split applications (OPTS), and an unamended control (UC)] on N2O fluxes and season-long emissions in a greenhouse trial simulating a furrow-irrigated rice production system. Gas collection occurred weekly over the 2018 and 2019 rice growing seasons for the field study and during 2020 growing season for the greenhouse trial. In 2018, N2O emissions differed (P \u3c 0.1) among site positions and differed between tillage treatments, while 2019 emissions differed (P \u3c 0.1) only between tillage treatments. Nitrous oxide emissions in 2018 were greatest at the down-slope position (3.34 kg N2O ha-1 season-1) compared to both the mid- (2.78 kg N2O ha-1 season-1) and up-slope (2.74 kg N2O ha-1 season-1) positions, which did not differ. For both growing seasons, CT produced greater (P \u3c 0.1) N2O emissions than NT, where mean annual emissions from CT were 3.15 and 2.58 kg N2O ha-1 season-1 for the 2018 and 2019 seasons, respectively. In 2020, N2O fluxes differed among fertilizer-N treatments over time (P \u3c 0.01), yet there was no consistent trend between mid-season fertilizer-N application timing and the timing of peak N2O fluxes. Nitrous oxide emissions numerically ranged from 0.42 kg N2O ha-1 season-1 from the UC to 0.65 kg N2O ha-1 season-1 from the OPOS treatment, but unlike fluxes, did not differ (P = 0.60) among N-fertilizer treatments. Results of these studies highlight the importance of soil management practices and water regimes in regulating N2O production and release from rice fields. The evaluation of N2O fluxes and emissions from furrow-irrigated rice is essential to understanding the environmental impact of furrow-irrigation as an alternative water management scheme for rice production

A critical period of progesterone withdrawal precedes menstruation in macaques

Macaques are menstruating nonhuman primates that provide important animal models for studies of hormonal regulation in the uterus. In women and macaques the decline of progesterone (P) at the end of the cycle triggers endometrial expression of a variety of matrix metalloproteinase (MMP) enzymes that participate in tissue breakdown and menstrual sloughing. To determine the minimal duration of P withdrawal required to induce menses, we assessed the effects of adding P back at various time points after P withdrawal on both frank bleeding patterns and endometrial MMP expression. Artificial menstrual cycles were induced by treating the animals sequentially with implants releasing estradiol (E(2)) and progesterone (P). To assess bleeding patterns, P implants were removed at the end of a cycle and then added back at 12, 24, 30, 36, 40, 48, 60, or 72 hours (h) after the initial P withdrawal. Observational analysis of frank bleeding patterns showed that P replacement at 12 and 24 h blocked menses, replacement at 36 h reduced menses but replacement after 36 h failed to block menses. These data indicate that in macaques, a critical period of P withdrawal exists and lasts approximately 36 h. In other similarly cycled animals, we withdrew P and then added P back either during (12–24 h) or after (48 h) the critical period, removed the uterus 24 h after P add back and evaluated endometrial MMP expression. Immunocytochemistry showed that replacement of P during the critical period suppressed MMP-1, -2 and -3 expression along with menses, but replacement of P at 48 h, which failed to suppress mense, suppressed MMP-1 and MMP-3 but did not block MMP-2. We concluded that upregulation of MMPs is essential to menses induction, but that after the critical period, menses will occur even if some MMPs are experimentally blocked

Research poster: Climate change science for northern Nevada educators

Research poste

Cracking the Off the Grid Password Solution

Authentication and authorization to online sites is a difficult problem to solve without the use of cryptography. The standard method of using passwords is clearly an insecure method of authentication. A method of authenticating users utilizing a Latin square was developed by a security enthusiast and touted as secure. This paper demonstrates a novel method of cracking the Latin squares that are used to generate the secure passwords in the Off The Grid (OTG) password management scheme. Our method leverages the cores on Graphics Processing Unit (GPU) using the Compute Unified Device Architecture (CUDA) programming extension to efficiently solve the Latin squares used in the OTG password management solution. We developed a model that represents the possible states and the constraints of the OTG system. We show that the OTG system leaks information about its Latin square and we provide supporting evidence through examples and computation

Internet Safety: Positioning VCU as a National Leader in Internet Safety

While a multitude of information from a host of sources exists on how to keep children safe on the Internet, there is not a unified effort to combine it all and get it to the right people. This is not a plan to teach college students about Internet safety. This is a proposal to begin much earlier, targeting middle-school aged children and their parents, many of whom have no idea of the dangers – and opportunities – that exist in cyberspace