142 research outputs found
TIME-DOMAIN AND FREQUENCY-DOMAIN REFLECTOMETRY TYPE SOIL MOISTURE SENSOR PERFORMANCE AND SOIL TEMPERATURE EFFECTS IN FINE- AND COARSE-TEXTURED SOILS
The performances of six time-domain reflectometry (TDR) and frequency-domain reflectometry (FDR) type soil moisture sensors were investigated for measuring volumetric soil-water content (θv) in two different soil types. Soil-specific calibration equations were developed for each sensor using calibrated neutron probe-measured θv. Sensors were also investigated for their performance response in measuring θv to changes in soil temperature. The performance of all sensors was significantly different (P\u3c0.05) than the neutron probe-measured θv, with the same sensor also exhibiting variation between soils. In the silt loam soil, the 5TE sensor had the lowest root mean squared error (RMSE) of 0.041 m3/m3, indicating the best performance among all sensors investigated. The performance ranking of the other sensors from high performance to low was: TDR300 (High Clay Mode), CS616 (H) and 10HS, SM150, TDR300 (Standard Mode), and CS616 (V) (H: horizontal installation and V: vertical installation). In the loamy sand, the CS616 (H) performed best with an RMSE of 0.014 m3/m3 and the performance ranking of other sensors was: 5TE, CS616 (V), TDR300 (S), SM150, and 10HS. When θv was near or above field capacity, the performance error of most sensors increased. Most sensors exhibited a linear response to increase in soil temperature. Most sensors exhibited substantial sensitivity to changes in soil temperature and the θv response of the same sensor to high vs. normal soil temperatures differed significantly between the soils. All sensors underestimated θv in high temperature range in both soils. The ranking order of the magnitude of change in θv in response to 1°C increase in soil temperature (from the lowest to the greatest impact of soil temperature on sensor performance) in silt loam soil was: SM150, 5TE, TDR300 (S), 10HS, CS620, CS616 (H), and CS616 (V). The ranking order from lower to higher sensitivity to soil temperature changes in loamy sand was: 10HS, CS616 (H), 5TE, CS616 (V), SM150, and TDR300 (S). When the data from all sensors and soils are pooled, the overall average of change in θv for a 1°C increase in soil temperature was 0.21 m3/m3 in silt loam soil and -0.052 m3/m3 in loamy sand. When all TDR- and FDR-type sensors were pooled separately for both soils, the average change in θv for a 1°C increase in soil temperature for the TDR- and FDR-type sensors was 0.1918 and -0.0273 m3/m3, respectively, indicating that overall TDR-type sensors are more sensitive to soil temperature changes than FDR-type sensors when measuring θv
Flow- and context-sensitive points-to analysis using generalized points-to graphs
© Springer-Verlag GmbH Germany 2016. Bottom-up interprocedural methods of program analysis construct summary flow functions for procedures to capture the effect of their calls and have been used effectively for many analyses. However, these methods seem computationally expensive for flow- and context- sensitive points-to analysis (FCPA) which requires modelling unknown locations accessed indirectly through pointers. Such accesses are com- monly handled by using placeholders to explicate unknown locations or by using multiple call-specific summary flow functions. We generalize the concept of points-to relations by using the counts of indirection levels leaving the unknown locations implicit. This allows us to create sum- mary flow functions in the form of generalized points-to graphs (GPGs) without the need of placeholders. By design, GPGs represent both mem- ory (in terms of classical points-to facts) and memory transformers (in terms of generalized points-to facts). We perform FCPA by progressively reducing generalized points-to facts to classical points-to facts. GPGs distinguish between may and must pointer updates thereby facilitating strong updates within calling contexts. The size of GPGs is linearly bounded by the number of variables and is independent of the number of statements. Empirical measurements on SPEC benchmarks show that GPGs are indeed compact in spite of large procedure sizes. This allows us to scale FCPA to 158 kLoC using GPGs (compared to 35 kLoC reported by liveness-based FCPA). Thus GPGs hold a promise of efficiency and scalability for FCPA without compro- mising precision
Factors associated with long-term species composition in dry tropical forests of Central India
The long-term future of species composition in forests depends on regeneration. Many factors can affect regeneration, including human use, environmental conditions, and species' traits. This study examines the influence of these factors in a tropical deciduous forest of Central India, which is heavily used by local, forest-dependent residents for livestock grazing, fuel-wood extraction, construction and other livelihood needs. We measure size-class proportions (the ratio of abundance of a species at a site in a higher size class to total abundance in both lower and higher size classes) for 39 tree species across 20 transects at different intensities of human use. The size-class proportions for medium to large trees and for small to medium-sized trees were negatively associated with species that are used for local construction, while size class proportions for saplings to small trees were positively associated with those species that are fire resistant and negatively associated with livestock density. Results indicate that grazing and fire prevent non-fire resistant species from reaching reproductive age, which can alter the long term composition and future availability of species that are important for local use and ecosystem services. Management efforts to reduce fire and forest grazing could reverse these impacts on long-term forest composition
Software Model Checking with Explicit Scheduler and Symbolic Threads
In many practical application domains, the software is organized into a set
of threads, whose activation is exclusive and controlled by a cooperative
scheduling policy: threads execute, without any interruption, until they either
terminate or yield the control explicitly to the scheduler. The formal
verification of such software poses significant challenges. On the one side,
each thread may have infinite state space, and might call for abstraction. On
the other side, the scheduling policy is often important for correctness, and
an approach based on abstracting the scheduler may result in loss of precision
and false positives. Unfortunately, the translation of the problem into a
purely sequential software model checking problem turns out to be highly
inefficient for the available technologies. We propose a software model
checking technique that exploits the intrinsic structure of these programs.
Each thread is translated into a separate sequential program and explored
symbolically with lazy abstraction, while the overall verification is
orchestrated by the direct execution of the scheduler. The approach is
optimized by filtering the exploration of the scheduler with the integration of
partial-order reduction. The technique, called ESST (Explicit Scheduler,
Symbolic Threads) has been implemented and experimentally evaluated on a
significant set of benchmarks. The results demonstrate that ESST technique is
way more effective than software model checking applied to the sequentialized
programs, and that partial-order reduction can lead to further performance
improvements.Comment: 40 pages, 10 figures, accepted for publication in journal of logical
methods in computer scienc
A Postulate for Tiger Recovery: The Case of the Caspian Tiger
Recent genetic analysis has shown that the extinct Caspian Tiger (P. t. virgata) and the living Amur Tigers (P. t. altaica) of the Russian Far East are actually taxonomically synonymous and that Caspian and Amur groups historically formed a single population, only becoming separated within the last 200 years by human agency. A major conservation implication of this finding is that tigers of Amur stock might be reintroduced, not only back into the Koreas and China as is now proposed, but also through vast areas of Central Asia where the Caspian tiger once lived. However, under the current tiger conservation framework the 12 “Caspian Tiger States” are not fully involved in conservation planning. Equal recognition as “Tiger Range States” should be given to the countries where the Caspian tiger once lived and their involvement in tiger conservation planning encouraged. Today, preliminary ecological surveys show that some sparsely populated areas of Central Asia preserve natural habitat suitable for tigers. In depth assessments should be completed in these and other areas of the Caspian range to evaluate the possibility of tiger reintroductions. Because tigers are a charismatic umbrella species, both ecologically and politically, reintroduction to these landscapes would provide an effective conservation framework for the protection of many species in addition to tigers. And for today’s Amur Tigers this added range will provide a buffer against further loss of genetic diversity, one which will maintain that diversity in the face of selective pressures that can only be experienced in the wild
Planning Technologies for Interactive Storytelling
Since AI planning was first proposed for the task of narrative generation in interactive storytelling (IS), it has emerged as the dominant approach in this field. This chapter traces the use of planning technologies in this area, considers the core issues involved in the application of planning technologies in IS, and identifies some of the remaining challenges
Tigers of Sundarbans in India: Is the Population a Separate Conservation Unit?
The Sundarbans tiger inhabits a unique mangrove habitat and are morphologically distinct from the recognized tiger subspecies in terms of skull morphometrics and body size. Thus, there is an urgent need to assess their ecological and genetic distinctiveness and determine if Sundarbans tigers should be defined and managed as separate conservation unit. We utilized nine microsatellites and 3 kb from four mitochondrial DNA (mtDNA) genes to estimate genetic variability, population structure, demographic parameters and visualize historic and contemporary connectivity among tiger populations from Sundarbans and mainland India. We also evaluated the traits that determine exchangeability or adaptive differences among tiger populations. Data from both markers suggest that Sundarbans tiger is not a separate tiger subspecies and should be regarded as Bengal tiger (P. t. tigris) subspecies. Maximum likelihood phylogenetic analyses of the mtDNA data revealed reciprocal monophyly. Genetic differentiation was found stronger for mtDNA than nuclear DNA. Microsatellite markers indicated low genetic variation in Sundarbans tigers (He= 0.58) as compared to other mainland populations, such as northern and Peninsular (Hebetween 0.67- 0.70). Molecular data supports migration between mainland and Sundarbans populations until very recent times. We attribute this reduction in gene flow to accelerated fragmentation and habitat alteration in the landscape over the past few centuries. Demographic analyses suggest that Sundarbans tigers have diverged recently from peninsular tiger population within last 2000 years. Sundarbans tigers are the most divergent group of Bengal tigers, and ecologically non-exchangeable with other tiger populations, and thus should be managed as a separate "evolutionarily significant unit" (ESU) following the adaptive evolutionary conservation (AEC) concept.Wildlife Institute of India, Dehra Dun (India)
Deregulation of CREB Signaling Pathway Induced by Chronic Hyperglycemia Downregulates NeuroD Transcription
CREB mediates the transcriptional effects of glucose and incretin hormones in insulin-target cells and insulin-producing β-cells. Although the inhibition of CREB activity is known to decrease the β-cell mass, it is still unknown what factors inversely alter the CREB signaling pathway in β-cells. Here, we show that β-cell dysfunctions occurring in chronic hyperglycemia are not caused by simple inhibition of CREB activity but rather by the persistent activation of CREB due to decreases in protein phophatase PP2A. When freshly isolated rat pancreatic islets were chronically exposed to 25 mM (high) glucose, the PP2A activity was reduced with a concomitant increase in active pCREB. Brief challenges with 15 mM glucose or 30 µM forskolin after 2 hour fasting further increased the level of pCREB and consequently induced the persistent expression of ICER. The excessively produced ICER was sufficient to repress the transcription of NeuroD, insulin, and SUR1 genes. In contrast, when islets were grown in 5 mM (low) glucose, CREB was transiently activated in response to glucose or forskolin stimuli. Thus, ICER expression was transient and insufficient to repress those target genes. Importantly, overexpression of PP2A reversed the adverse effects of chronic hyperglycemia and successfully restored the transient activation of CREB and ICER. Conversely, depletion of PP2A with siRNA was sufficient to disrupt the negative feedback regulation of CREB and induce hyperglycemic phenotypes even under low glucose conditions. Our findings suggest that the failure of the negative feedback regulation of CREB is the primary cause for β-cell dysfunctions under conditions of pathogenic hyperglycemia, and PP2A can be a novel target for future therapies aiming to protect β-cells mass in the late transitional phase of non-insulin dependent type 2 diabetes (NIDDM)
GLP-1 Analogs Reduce Hepatocyte Steatosis and Improve Survival by Enhancing the Unfolded Protein Response and Promoting Macroautophagy
Nonalcoholic fatty liver disease (NAFLD) is a known outcome of hepatosteatosis. Free fatty acids (FFA) induce the unfolded protein response (UPR) or endoplasmic reticulum (ER) stress that may induce apoptosis. Recent data indicate ER stress to be a major player in the progression of fatty liver to more aggressive lesions. Autophagy on the other hand has been demonstrated to be protective against ER stress-induced cell death. We hypothesized that exendin-4 (GLP-1 analog) treatment of fat loaded hepatocytes can reduce steatosis by autophagy which leads to reduced ER stress-related hepatocyte apoptosis.Primary human hepatocytes were loaded with saturated, cis- and trans-unsaturated fatty acids (palmitic, oleic and elaidic acid respectively). Steatosis, induced with all three fatty acids, was significantly resolved after exendin-4 treatment. Exendin-4 sustained levels of GRP78 expression in fat-loaded cells when compared to untreated fat-loaded cells alone. In contrast, CHOP (C/EBP homologous protein); the penultimate protein that leads to ER stress-related cell death was significantly decreased by exendin-4 in hepatocytes loaded with fatty acids. Finally, exendin-4 in fat loaded hepatocytes clearly promoted gene products associated with macroautophagy as measured by enhanced production of both Beclin-1 and LC3B-II, markers for autophagy; and visualized by transmission electron microscopy (TEM). Similar observations were made in mouse liver lysates after mice were fed with high fat high fructose diet and treated with a long acting GLP-1 receptor agonist, liraglutide.GLP-1 proteins appear to protect hepatocytes from fatty acid-related death by prohibition of a dysfunctional ER stress response; and reduce fatty acid accumulation, by activation of both macro-and chaperone-mediated autophagy. These findings provide a novel role for GLP-1 proteins in halting the progression of more aggressive lesions from underlying steatosis in humans afflicted with NAFLD
Primary pancreatic lymphoma – pancreatic tumours that are potentially curable without resection, a retrospective review of four cases
BACKGROUND: Primary pancreatic lymphomas (PPL) are rare tumours of the pancreas. Symptoms, imaging and tumour markers can mimic pancreatic adenocarcinoma, but they are much more amenable to treatment. Treatment for PPL remains controversial, particularly the role of surgical resection. METHODS: Four cases of primary pancreatic lymphoma were identified at Prince of Wales Hospital, Sydney, Australia. A literature review of cases of PPL reported between 1985 and 2005 was conducted, and outcomes were contrasted. RESULTS: All four patients presented with upper abdominal symptoms associated with weight loss. One case was diagnosed without surgery. No patients underwent pancreatectomy. All patients were treated with chemotherapy and radiotherapy, and two of four patients received rituximab. One patient died at 32 months. Three patients are disease free at 15, 25 and 64 months, one after successful retreatment. Literature review identified a further 103 patients in 11 case series. Outcomes in our series and other series of chemotherapy and radiotherapy compared favourably to surgical series. CONCLUSION: Biopsy of all pancreatic masses is essential, to exclude potentially curable conditions such as PPL, and can be performed without laparotomy. Combined multimodality treatment, utilising chemotherapy and radiotherapy, without surgical resection is advocated but a cooperative prospective study would lead to further improvement in treatment outcomes
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