Pharmacokinetic Analysis of Gd-DTPA Enhancement in dynamic three-dimensional MRI of breast lesions

The purpose of this study was to demonstrate that dynamic MRI covering both breasts can provide sensitivity for tumor detection as well as specificity and sensitivity for differentiation of tumor malignancy. Three-dimensional gradient echo scans were used covering both breasts. Before Gd-DTPA bolus injection, two scans were obtained with different flip angles, and after injection, a dynamic series followed. Thirty-two patients were scanned according to this protocol. From these scans, in addition to enhancement, the value of T1 before injection was obtained. This was used to estimate the concentration of Gd-DTPA as well as the pharmacokinetic parameters governing its time course. Signal enhancement in three-dimensional dynamic scanning was shown to be a sensitive basis for detection of tumors. In our series, all but two mam-mographically suspicious lesions did enhance, and in three cases, additional enhancing lesions were found, two of which were in the contralateral breast. The parameter most suited for classification of breast lesions into benign or malignant was shown to be the pharmacokinetically defined permeability k31, which, for that test, gave a sensitivity of 92% and a specificity of 70%. Our three-dimensional dynamic MRI data are sensitive for detection of mammographically occult breast tumors and specific for classification of these as benign or malignant

Online discussion compensates for suboptimal timing of supportive information presentation in a digitally supported learning environment

This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation (information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction than those who received information only before each cluster. The students within the two separate information presentation conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster, online discussion led to better results than personal discussion. When supportive information had been presented during the learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction. Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the learning task clusters in IDLM

Dissimilar response of plant and soil biota communities to long-term nutrient adition in grasslands

The long-term effect of fertilizers on plant diversity and productivity is well known, but long-term effects on soil biota communities have received relatively little attention. Here, we used an exceptional long-lasting (>40 years) grassland fertilization experiment to investigate the long-term effect of Ca, N, PK, and NPK addition on the productivity and diversity of both vegetation and soil biota. Whereas plant diversity increased by liming and decreased by N and NPK, the diversity of nematodes, collembolans, mites, and enchytraeids increased by N, PK, or NPK. Fertilization with NPK and PK increased plant biomass and biomass of enchytraeids and collembolans. Biomass of nematodes and earthworms increased by liming. Our results suggest that soil diversity might be driven by plant productivity rather than by plant diversity. This may imply that the selection of measures for restoring or conserving plant diversity may decrease soil biota diversity. This needs to be tested in future experiment

Gene expression patterns in anterior pituitary associated with quantitative measure of oestrous behaviour in dairy cows

Intensive selection for high milk yield in dairy cows has raised production levels substantially but at the cost of reduced fertility, which manifests in different ways including reduced expression of oestrous behaviour. The genomic regulation of oestrous behaviour in bovines remains largely unknown. Here, we aimed to identify and study those genes that were associated with oestrous behaviour among genes expressed in the bovine anterior pituitary either at the start of oestrous cycle or at the mid-cycle (around day 12 of cycle), or regardless of the phase of cycle. Oestrous behaviour was recorded in each of 28 primiparous cows from 30 days in milk onwards till the day of their sacrifice (between 77 and 139 days in milk) and quantified as heat scores. An average heat score value was calculated for each cow from heat scores observed during consecutive oestrous cycles excluding the cycle on the day of sacrifice. A microarray experiment was designed to measure gene expression in the anterior pituitary of these cows, 14 of which were sacrificed at the start of oestrous cycle (day 0) and 14 around day 12 of cycle (day 12). Gene expression was modelled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model on data from day 0 cows alone (analysis 1), day 12 cows alone (analysis 2) and the combined data from day 0 and day 12 cows (analysis 3). Genes whose expression patterns showed significant linear or non-linear relationships with average heat scores were identified in all three analyses (177, 142 and 118 genes, respectively). Gene ontology terms enriched among genes identified in analysis 1 revealed processes associated with expression of oestrous behaviour whereas the terms enriched among genes identified in analysis 2 and 3 were general processes which may facilitate proper expression of oestrous behaviour at the subsequent oestrus. Studying these genes will help to improve our understanding of the genomic regulation of oestrous behaviour, ultimately leading to better management strategies and tools to improve or monitor reproductive performance in bovines

Management of preterm labor: atosiban or nifedipine?

Preterm birth is strongly associated with neonatal death and long-term neurological morbidity. The purpose of tocolytic drug administration is to postpone threatening preterm delivery for 48 hours to allow maximal effect of antenatal corticosteroids and maternal transportation to a center with specialized neonatal care facilities. There is uncertainty about the value of atosiban (oxytocin receptor antagonist) and nifedipine (calcium channel blocker) as first-line tocolytic drugs in the management of preterm labor. For nifedipine, concerns have been raised about unproven safety, lack of placebo-controlled trials, and its off-label use. The tocolytic efficacy of atosiban has also been questioned because of a lack of reduction in neonatal morbidity. This review discusses the available evidence, the pros and cons of either drug and aims to provide information to support a balanced choice of first-line tocolytic drug: atosiban or nifedipine

SPH Simulations of Galactic Gaseous Disk with Bar: Distribution and Kinematic Structure of Molecular Clouds toward the Galactic Center

We have performed Smoothed Particle Hydrodynamic (SPH) simulations to study the response of molecular clouds in the Galactic disk to a rotating bar and their subsequent evolution in the Galactic Center (GC) region. The Galactic potential in our models is contributed by three axisymmetric components (massive halo, exponential disk, compact bulge) and a non-axisymmetric bar. These components are assumed to be invariant in time in the frame corotating with the bar. Some noticeable features such as an elliptical outer ring, spiral arms, a gas-depletion region, and a central concentration have been developed due to the influence of the bar. The rotating bar induces non-circular motions of the SPH particles, but hydrodynamic collisions tend to suppress the random components of the velocity. The velocity field of the SPH particles is consistent with the kinematics of molecular clouds observed in HCN (1-0) transition; these clouds are thought to be very dense clouds. However, the l-v diagram of the clouds traced by CO is quite different from that of our SPH simulation, being more similar to that obtained from simulations using collisionless particles. The $l-v$ diagram of a mixture of collisional and collisionless particles gives better reproduction of the kinematic structures of the GC clouds observed in the CO line. The fact that the kinematics of HCN clouds can be reproduced by the SPH particles suggests that the dense clouds in the GC are formed via cloud collisions induced by rotating bar.Comment: 31 pages, 10 pigures, accepted for publication in Ap

Tracking Cyber Adversaries with Adaptive Indicators of Compromise

A forensics investigation after a breach often uncovers network and host indicators of compromise (IOCs) that can be deployed to sensors to allow early detection of the adversary in the future. Over time, the adversary will change tactics, techniques, and procedures (TTPs), which will also change the data generated. If the IOCs are not kept up-to-date with the adversary's new TTPs, the adversary will no longer be detected once all of the IOCs become invalid. Tracking the Known (TTK) is the problem of keeping IOCs, in this case regular expressions (regexes), up-to-date with a dynamic adversary. Our framework solves the TTK problem in an automated, cyclic fashion to bracket a previously discovered adversary. This tracking is accomplished through a data-driven approach of self-adapting a given model based on its own detection capabilities. In our initial experiments, we found that the true positive rate (TPR) of the adaptive solution degrades much less significantly over time than the naive solution, suggesting that self-updating the model allows the continued detection of positives (i.e., adversaries). The cost for this performance is in the false positive rate (FPR), which increases over time for the adaptive solution, but remains constant for the naive solution. However, the difference in overall detection performance, as measured by the area under the curve (AUC), between the two methods is negligible. This result suggests that self-updating the model over time should be done in practice to continue to detect known, evolving adversaries.Comment: This was presented at the 4th Annual Conf. on Computational Science & Computational Intelligence (CSCI'17) held Dec 14-16, 2017 in Las Vegas, Nevada, US

Fetal Urine Production in Late Pregnancy

Objective. Hourly fetal urine production rate (HFUPR) was studied in relation to both gestational age and the onset of spontaneous labor in normal term human pregnancies. Methods. Serial volume measurements were obtained from longitudinal ultrasound images of the fetal bladder at 1–5-minute intervals, and HFUPR was subsequently calculated. A total of 178 adequate bladder-filling cycles were recorded in 112 women, and the amniotic fluid index (AFI) was assessed. Results. HFUPR did not change significantly between 37 and 42 weeks' gestation. However, HFUPR decreased during the last 14 days prior to the onset of spontaneous labor (P < 0.005). No significant correlation was found between HFUPR and AFI, neither when measured at the same time nor when HFUPR and AFI were measured at various intervals in time. Conclusion. HFUPR falls before and in relation to the time of onset of labor rather than in relation to gestational age

A systematic literature review of the major factors causing yield gap by affecting growth, feed conversion ratio and survival in Nile tilapia (Oreochromis niloticus)

Abstract Productivity among small- and medium-scale tilapia farms varies considerably. The difference between the best performers and lower ones (yield gap), is affected by differences in growth rate and feed conversion ratio (FCR). FCR at the farm level is strongly influenced by survival of fish. In this study a systematic literature review of two databases (ASFA and CAB-Abstracts) identified 1973 potentially relevant articles. Data from 32 articles that met the inclusion criteria were analysed using linear mixed models for the most important factors with significant contributions to growth [investigated through analysis of the thermal growth coefficient (TGC)], survival and FCR of Nile tilapia. Increasing crude protein (CP), dissolved oxygen (DO) and pH significantly decreased FCR and increased TGC. Increasing stocking weight (SW) significantly improved both FCR and survival. Temperature had the largest effect on FCR followed by DO, pH and CP. DO had the largest effect on TGC followed by CP and pH. This study confirms that the optimal rearing temperature for Nile tilapia is between 27 and 32°C. Improving management to optimize DO (> 5 mg/L), stocking density (3–5 fish/m2), SW (> 10 g) and CP (25 − 30%) will improve performance and survival in small- and medium-scale tilapia farming. However, it is hard to influence temperature in ponds and cages while DO is largely influenced by aeration. Since many small- and medium-sized farms do not have aeration, these major tilapia farming systems could benefit from genetically improved strains selected for resilience to highly fluctuating diurnal temperature and DO levels

Novel spin-liquid states in the frustrated Heisenberg antiferromagnet on the honeycomb lattice

Recent experiment on a honeycomb-lattice Heisenberg antiferromagnet (AF) Bi$_3$Mn$_4$O$_{12}$(NO$_3$) revealed a novel spin-liquid-like behavior down to low temperature, which was ascribed to the frustration effect due to the competition between the AF nearest- and next-nearest-neighbor interactions $J_1$ and $J_2$. Motivated by the experiment, we study the ordering of the $J_1$ -$J_2$ frustrated classical Heisenberg AF on a honeycomb lattice both by a low-temperature expansion and a Monte Carlo simulation. The model has been known to possess a massive degeneracy of the ground state, which, however, might be lifted due to thermal fluctuations leading to a unique ordered state, the effect known as 'order-by-disorder'. We find that the model exhibits an intriguing ordering behavior, particularly near the AF phase boundary. The energy scale of the order-by-disorder is suppressed there down to extremely low temperatures, giving rise to exotic spin-liquid states like a "ring-liquid" or a "pancake-liquid" state accompanied by the characteristic spin structure factor and the field-induced antiferromagnetism. We argue that the recent experimental data are explicable if the system is in such exotic spin-liquid states