bluuebunny/crossref_metadata_2025 huggingface dataset:
Degradation of SAMHD1 by Vpx Is Independent of Uncoating
Authors: Jáuregui Paula , Logue Eric C. , Schultz Megan L. , Fung Stephanie , Landau Nathaniel R.
Published: March 2015

Sterile alpha motif domain and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) replication in myeloid and resting T cells. Lentiviruses such as HIV-2 and some simian immunodeficiency viruses (SIVs) counteract the restriction by encoding Vpx or Vpr, accessory proteins that are packaged in virions and which, upon entry of the virus into the cytoplasm, induce the proteasomal degradation of SAMHD1. As a tool to study these mechanisms, we generated HeLa cell lines that express a fusion protein termed NLS.GFP.SAM595 in which the Vpx binding domain of SAMHD1 is fused to the carboxy terminus of green fluorescent protein (GFP) and a nuclear localization signal is fused to the amino terminus of GFP. Upon incubation of Vpx-containing virions with the cells, the NLS.GFP.SAM595 fusion protein was degraded over several hours and the levels remained low over 5 days as the result of continued targeting of the CRL4 E3 ubiquitin ligase. Degradation of the fusion protein required that it contain a nuclear localization sequence. Fusion to the cytoplasmic protein muNS rendered the protein resistant to Vpx-mediated degradation, confirming that SAMHD1 is targeted in the nucleus. Virions treated with protease inhibitors failed to release Vpx, indicating that Gag processing was required for Vpx release from the virion. Mutations in the capsid protein that altered the kinetics of virus uncoating and the Gag binding drug PF74 had no effect on the Vpx-mediated degradation. These results suggest that Vpx is released from virions without a need for uncoating of the capsid, allowing Vpx to transit to the nucleus rapidly upon entry into the cytoplasm.

IMPORTANCE
SAMHD1 restricts lentiviral replication in myeloid cells and resting T cells. Its importance is highlighted by the fact that viruses such as HIV-2 encode an accessory protein that is packaged in the virion and is dedicated to inducing SAMHD1 degradation. Vpx needs to act rapidly upon infection to allow reverse transcription to proceed. The limited number of Vpx molecules in a virion also needs to clear the cell of SAMHD1 over a prolonged period of time. Using an engineered HeLa cell line that expresses a green fluorescent protein (GFP)-SAMHD1 fusion protein, we showed that the Vpx-dependent degradation occurs without a need for viral capsid uncoating. In addition, the fusion protein was degraded only when it was localized to the nucleus, confirming that SAMHD1 is targeted in the nucleus and thus explaining why Vpx also localizes to the nucleus.
Do small doses of atropine (<0.1 mg) cause bradycardia in young children?
Authors: Eisa Lara , Passi Yuvesh , Lerman Jerrold , Raczka Michelle , Heard Christopher
Published: March 2015

Objective

To determine the heart rate response to atropine (<0.1 mg) in anaesthetised young infants.

Design

Prospective, observational and controlled.

Setting

Elective surgery.

Patients

Sixty unpremedicated healthy infants less than 15 kg were enrolled. Standard monitoring was applied. Anaesthesia was induced by mask with nitrous oxide (66%) and oxygen (33%) followed by sevoflurane (8%).

Interventions

Intravenous (IV) atropine (5 µg/kg) was flushed into a fast flowing IV. The ECG was recorded continuously from 30 s before the atropine until 5 min afterwards.

Main outcome measures

The incidence of bradycardia and arrhythmias was determined from the ECGs by a blinded observer.

Results

The median (IQR) age was 6.5 (4–12) months and the mean (95% CI) weight was 8.6 (8.1 to 9.1) kg. The mean (95% CI) dose of atropine was 40.9 (37.3 to 44) µg. Bradycardia did not occur. Two infants developed premature atrial contractions and one developed a premature ventricular contraction. When compared with baseline values, heart rate increased by 7% 30 s after atropine, 14% 1 min after atropine and 25% 5 min after atropine. Twenty-nine infants (48%) experienced tachycardia (>20% above baseline rate) after atropine lasting 222.7 s (range 27.9–286). The change in heart rate 5 min after atropine was inversely related to the baseline heart rate.

Conclusions

The upper 95% CI for the occurrence of bradycardia in the entire population of infants based on a zero incidence in this study is 5%. These results rebut the notion that atropine <0.1 mg IV causes bradycardia in young infants.

Trial registration number

ClinicalTrials.gov #NCT01819064.
Incidental detection of ascariasis worms on USG in a protein energy malnourished (PEM) child with abdominal pain
Authors: Suthar Pokhraj Prakashchandra , Doshi Rajkumar Prakashbhai , Mehta Chetan , Vadera Khyati P
Published: March 2015

A 10-year-old child presented with dull aching periumbilical abdominal pain for 15 days. The child was not gaining weight despite a good appetite. Physical examination of the child revealed grade-I protein energy malnourishment (PEM) according to IAP (Indian Academic of Paediatrics) classification. The rest of the systemic examination was normal. Routine blood investigation revealed anaemia with eosinophilia. Abdominal ultrasonography did not show any abnormality with curvilinear transducer (3.5–5 MHz), however, linear ultrasound transducer (7.5–12 MHz) with harmonic tissue imaging showed worms in the lumen of the small intestine with curling movement on real time scanning. Stool examination for the eggs of ascariasis was positive. The patient was treated with antihelminthic drugs. Dietary modification for the PEM was advised. After 3 months of treatment, the patient improved and stool examination forAscariswas negative on follow-up.
Accessory pancreatic lobe with gastric duplication cyst: diagnostic challenges of a rare congenital anomaly
Authors: Jain Abhilasha S , Patel Avani M , Jain Sharad R , Thakkar Ashok
Published: March 2015

Reports of combined congenital abnormalities of gastric duplication cysts and accessory pancreatic lobes are rarely reported. Patients with such anomalies may require appropriate surgical intervention tailored to the individual patient for complete cure. A multimodality diagnostic approach using ultrasonography, CT and MRI is useful for appreciation of the relevant anatomy of the congenital abnormality and for proper surgical planning. We present a case of a gastric duplication cyst with accessory pancreatic lobe and ectopic pancreatic rest in a 5-year-old child presenting with symptoms of recurrent pancreatitis.
Renal pelvis rupture during pregnancy: diagnosing a confusing source of despair
Authors: Boekhorst Ferry , Bogers Hein , Martens Jolise
Published: March 2015

We present an impressive case of a pregnant woman presenting with severe right flank pains. A rare rupture of the right renal pelvis turned out to be the cause of her problems. Renal pelvis rupture in pregnancy is difficult to diagnose. It is easily confused with other more prevalent diagnoses, like hydronephrosis, ureteral distension, renal calculus and pyelonephritis. Ultrasonography is not always conclusive. Pyelography seems to be a good diagnostic tool, this case shows that MRI is another option. Renal pelvis rupture can be effectively treated with the insertion of a JJ-stent.
Gallstone pancreatitis secondary to a pathological cystic duct stump in a setting of chronic pain syndrome: a diagnostic dilemma
Authors: Gandhi Jamish , Tan Jeffrey , Gandhi Natasha
Published: March 2015

A 32-year-old woman presented with epigastric pain. She was a patient with chronic pain syndrome and had visited the emergency department several times over the past year. She did not drink alcohol. She had a laparoscopic cholecystectomy for gallstone pancreatitis 4 years ago. Her lipase was 2020 with normal bilirubin. MR cholangiopancreatography revealed a cystic structure resembling a gallbladder in the gallbladder fossa. This was in connection with the biliary system. The structure also contained stones. A review of the histology did confirm the gallbladder had been removed. She proceeded to have a laparoscopic re-cholecystectomy and made an unremarkable recovery.
Steroid-responsive encephalopathy: an under recognised aspect of Hashimoto's thyroiditis
Authors: Riangwiwat Tanawan , Sangtian Jutarat , Sriphrapradang Chutintorn
Published: March 2015

We present a case of a patient who was diagnosed with Hashimoto's encephalopathy based on the presence of subacute behavioural changes, negative work up for infection and immunological serology except for high serum titres of thyroid autoantibodies. Thyroid function tests (TFTs) and MRI of the brain were normal. EEG showed low amplitude, slow waves and θ waves at both frontal areas. His condition improved dramatically after treated with high-dose glucocorticoid. After 2 years of a relapsing–remitting course, a new episode occurred. There was an abrupt change of TFTs within 5 days: free thyroxine (fT4) from 1.52 to 1.53 ng/mL, free triiodothyronine (fT3) from 3.25 to >30 pg/mL and thyroid-stimulating hormone (TSH) from 5.08 to 0.78 mIU/L. On the following day found fT4 2.58, fT3 14.67 and TSH 0.042. The patient was diagnosed with Hashitoxicosis. High-dose glucocorticoid and β-blockers were initiated. The symptoms gradually improved and TFTs normalised within 2 weeks.
Disease history and risk of comorbidity in women's life course: a comprehensive analysis of the Japan Nurses’ Health Study baseline survey
Authors: Nagai Kazue , Hayashi Kunihiko , Yasui Toshiyuki , Katanoda Kota , Iso Hiroyasu , Kiyohara Yutaka , Wakatsuki Akihiko , Kubota Toshiro , Mizunuma Hideki
Published: March 2015

Objective

To classify diseases based on age at peak incidence to identify risk factors for later disease in women's life course.

Design

A cross-sectional baseline survey of participants in the Japan Nurses’ Health Study.

Setting

A nationwide prospective cohort study on the health of Japanese nurses. The baseline survey was conducted between 2001 and 2007 (n=49 927).

Main outcome measures

Age at peak incidence for 20 diseases from a survey of Japanese women was estimated using the Kaplan-Meier method with the Kernel smoothing technique. The incidence rate and peak incidence for diseases whose peak incidence occurred before the age of 45 years or before the perimenopausal period were selected as early-onset diseases. The OR and 95% CI were estimated to examine the risk of comorbidity between early-onset and other diseases.

Results

Four early-onset diseases (endometriosis, anaemia, migraine headache and uterine myoma) were significantly correlated with one another. Late-onset diseases significantly associated (OR>2) with early-onset diseases included comorbid endometriosis with ovarian cancer (3.65 (2.16 to 6.19)), endometrial cancer (2.40 (1.14 to 5.04)) and cerebral infarction (2.10 (1.15 to 3.85)); comorbid anaemia with gastric cancer (3.69 (2.68 to 5.08)); comorbid migraine with transient ischaemic attack (3.06 (2.29 to 4.09)), osteoporosis (2.11 (1.71 to 2.62)), cerebral infarction (2.04 (1.26 to 3.30)) and angina pectoris (2.00 (1.49 to 2.67)); and comorbid uterine myoma with colorectal cancer (2.31 (1.48 to 3.61)).

Conclusions

While there were significant associations between four early-onset diseases, women with a history of one or more of the early-onset diseases had a higher risk of other diseases later in their life course. Understanding the history of early-onset diseases in women may help reduce the subsequent risk of chronic diseases in later life.
Using a mass media campaign to raise women's awareness of the link between alcohol and cancer: cross-sectional pre-intervention and post-intervention evaluation surveys
Authors: Dixon Helen G , Pratt Iain S , Scully Maree L , Miller Jessica R , Patterson Carla , Hood Rebecca , Slevin Terry J
Published: March 2015

Objectives

To evaluate the effectiveness of a population-based, statewide public health intervention designed to improve women's awareness and knowledge of the link between alcohol and cancer.

Design

Cross-sectional tracking surveys conducted pre-intervention and post-intervention (waves I and III of campaign).

Setting

Western Australia.

Participants

Cross-sectional samples of Western Australian women aged 25–54 years before the campaign (n=136) and immediately after wave I (n=206) and wave III (n=155) of the campaign.

Intervention

The ‘Alcohol and Cancer’ mass media campaign ran from May 2010 to May 2011 and consisted of three waves of paid television advertising with supporting print advertisements.

Main outcome measures

Campaign awareness; knowledge of drinking guidelines and the link between alcohol and cancer; intentions towards drinking.

Results

Prompted recognition of the campaign increased from 67% following wave I to 81% following wave III (adjusted OR (adj OR)=2.31, 95% CI 1.33 to 4.00, p=0.003). Improvements in women's knowledge that drinking alcohol on a regular basis increases cancer risk were found following wave I (adj OR=2.60, 95% CI 1.57 to 4.30, p<0.001) and wave III (adj OR=4.88, 95% CI 2.55 to 9.36, p<0.001) compared with baseline. Knowledge of the recommended number of standard drinks for low risk in the long term increased between baseline and wave I (adj OR=1.68, 95% CI 1.02 to 2.76, p=0.041), but not baseline and wave III (adj OR=1.42, 95% CI 0.84 to 2.39, p=0.191). Among women who drink alcohol, the proportion expressing intentions to reduce alcohol consumption increased significantly between baseline and wave III (adj OR=2.38, 95% CI 1.11 to 5.12, p=0.026). However, no significant reductions in recent drinking behaviour were found following the campaign.

Conclusions

Results indicate a population-based mass media campaign can reach the target audience and raise awareness of links between alcohol and cancer, and knowledge of drinking guidelines. However, a single campaign may be insufficient to measurably curb drinking behaviour in a culture where pro-alcohol social norms and product marketing are pervasive.
Out-of-hours and weekend admissions to Danish medical departments: admission rates and 30-day mortality for 20 common medical conditions
Authors: Vest-Hansen Betina , Riis Anders Hammerich , Sørensen Henrik Toft , Christiansen Christian Fynbo
Published: March 2015

Objectives

Knowledge on timing of admissions and mortality for acute medical patients is limited. The aim of the study was to examine hospital admission rates and mortality rates for patients with common medical conditions according to time of admission.

Design

Nationwide population-based cohort study.

Setting

Population of Denmark.

Participants

Using the Danish National Registry of Patients covering all Danish hospitals, we identified all adults with the first acute admission to a medical department in Denmark during 2010.

Primary and secondary outcome measures

Hourly admission rates and age-standardised and sex-standardised 30-day mortality rates comparing weekday office hours, weekday out of hours, weekend daytime hours and weekend night-time hours.

Results

In total, 174 192 acute medical patients were included in the study. The admission rates (patients per hour) were 38.7 (95% CI 38.4 to 38.9) during weekday office hours, 13.3 (95% CI 13.2 to 13.5) during weekday out of hours, 19.8 (95% CI 19.6 to 20.1) during weekend daytime hours and 7.9 (95% CI 7.8 to 8.0) during weekend night-time hours. Admission rates varied between medical conditions. The proportion of patients admitted to an intensive care unit (ICU) increased outside of office hours. The age-standardised and sex-standardised 30-day mortality rate was 5.1% (95% CI 5.0% to 5.3%) after admission during weekday office hours, 5.7% (95% CI 5.5% to 6.0%) after admission during weekday out of hours, 6.4% (95% CI 6.1% to 6.7%) after admission during weekend daytime hours and 6.3% (95% CI 5.9% to 6.8%) after admission during weekend night-time hours. For the majority of the medical conditions examined, weekend admission was associated with highest mortality.

Conclusions

While admission rates decreased from office hours to weekend hours there was an observed increase in mortality. This may reflect differences in severity of illness as the proportion admitted to an ICU increased during the weekend.
Prostate biopsy concordance in a large population-based sample: a Surveillance, Epidemiology and End Results study
Authors: Schreiber David , Wong Andrew T , Rineer Justin , Weedon Jeremy , Schwartz David
Published: March 2015

Aims

To use the Surveillance, Epidemiology and End Results database in order to evaluate prostate biopsy concordance in a large population-based sample.

Methods

We identified 34 195 men who were diagnosed with prostate cancer and underwent a radical prostatectomy from 2010 to 2011. All patients also had to have both clinical and pathological Gleason scores available for analysis. The concordance of the biopsy Gleason score to the pathological Gleason score was analysed using the coefficient of agreement (κ). Univariate and multivariate logistic regression analyses were performed to determine potential factors that may impact concordance of Gleason score.

Results

Overall, the clinical and pathological Gleason scores matched in 55.4% of patients. The concordance rates were 55.3% for Gleason 6, 66.9% for Gleason 3+4, 42.9% for Gleason 4+3 and 24.8% for Gleason 8, with frequent downgrading to Gleason 7. The κ for Gleason score concordance was 0.36 (95% CI 0.35 to 0.37), indicating fair agreement. The weighted κ for Gleason score concordance was 0.51 (95% CI 0.50 to 0.52), indicating moderate agreement. Additionally, the Bowker tests of symmetry were highly significant (p<0.001), indicating that when discordant findings were present, pathological upgrading was more common than downgrading.

Conclusions

This study is, to our knowledge, the largest contemporary study of prostate biopsy concordance. We found that there continues to be significant Gleason migration both upward from biopsy Gleason 6 or 3+4 and downgrading from biopsy Gleason ≥8. Further studies are needed to better determine other potential genomic or biologic factors that may help increase the biopsy Gleason concordance.
Reproductive behavior of the wild carrotsDaucus pusillusandDaucus montanusfrom Argentina
Authors: Ibañez Maria S. , Camadro Elsa L.
Published: March 2015

Diploid Daucus pusillus Michx. (x = 11) and hexaploid Daucus montanus Humb. et Bonpl. ex Schult. (x = 11) are wild taxonomic carrot species, closely related to diploid Daucus carota L. (x = 9), spontaneous in Argentina. For efficient ex situ conservation and potential use in breeding, we investigated their reproductive behavior by (i) carrying out controlled pollinations among D. pusillus accessions from a wide distribution area in the country and between these and one plant of D. montanus that overlapped in flowering, and (ii) bagging a few inflorescences to prevent outcrossings. Part of the pollinated pistils were analyzed by fluorescence microscopy; others were left on the plant. Pollen viability was high (>87%) in all accessions, but heterogeneity for size and shape was observed. Seed formation in bagged inflorescences confirmed that D. pusillus is autogamous and revealed that D. montanus is self-compatible. Fully developed mericarps were obtained only in intraspecific combinations. It is concluded that populations classified as the taxonomic species D. pusillus constitute a biological species as well, and that they are closely related to the taxonomic species D. montanus because they share the basic chromosome number and are reproductively isolated mainly by post-zygotic barriers, which could be eventually circumvented via 2n gametes.
A survey on technologies for automatic forest fire monitoring, detection, and fighting using unmanned aerial vehicles and remote sensing techniques
Authors: Yuan Chi , Zhang Youmin , Liu Zhixiang
Published: March 2015

Because of their rapid maneuverability, extended operational range, and improved personnel safety, unmanned aerial vehicles (UAVs) with vision-based systems have great potential for monitoring, detecting, and fighting forest fires. Over the last decade, UAV-based forest fire fighting technology has shown increasing promise. This paper presents a systematic overview of current progress in this field. First, a brief review of the development and system architecture of UAV systems for forest fire monitoring, detection, and fighting is provided. Next, technologies related to UAV forest fire monitoring, detection, and fighting are briefly reviewed, including those associated with fire detection, diagnosis, and prognosis, image vibration elimination, and cooperative control of UAVs. The final section outlines existing challenges and potential solutions in the application of UAVs to forest firefighting.
Endotoxin exposure and puberty in female rats: the role of nitric oxide and caspase-1 inhibition in neonates
Authors: Ozgocer Tuba , Yildiz Sedat , Elbe Hulya , Vardi Nigar
Published: March 2015

Bacterial toxins are widespread in the environment as well as in the digestive system of humans and animals. Toxin from Gram-negative bacteria (endotoxin or lipopolysaccharide; LPS) has a life-long programming effect on reproduction in rats, but the mediators have not been well-documented, so we investigated the effects of LPS on the timing of puberty in female rats. Because the levels of nitric oxide (NO) and interleukin 1β (IL-1β) increase following injection of LPS, we injected neonates (post-natal day (pnd) 7) with LPS, with or without NO or IL-1β inhibitors. Half of the prepubescent (pnd 30) animals received an additional LPS injection. Vaginal opening, number of ovarian follicles, and serum anti-LPS antibodies were determined. A single LPS injection was sufficient to reduce the primordial follicle pool, but puberty was delayed when rats received 2 LPS injections (at pnd 7 and 30). NO or IL-1β inhibitors improved both of these parameters, suggesting that the early detrimental effects of LPS on puberty and primordial follicle pool are mediated by NO and IL-1β.
Structures of generalized loop super-Virasoro algebras
Authors: Dai Xiansheng , Han Jianzhi , Su Yucai
Published: March 2015

The structure theory of a class of generalized loop super-Virasoro algebras is studied in this paper. In particular, the derivation algebras, the automorphism groups and the second cohomology groups of generalized loop centerless supper-Virasoro algebras are determined completely.
Glauber dynamics on the cycles: Spectral distribution of the generator
Authors: Ko Chul Ki , Park Sang Don , Yoo Hyun Jae
Published: March 2015

We consider Glauber dynamics on finite cycles. By introducing a vacuum state we consider an algebraic probability space for the generator of the dynamics. We obtain a quantum decomposition of the generator and construct an interacting Fock space. As a result we obtain a distribution of the generator in the vacuum state. We also discuss the monotonicity of the moments of spectral measure as the couplings increase. In particular, when the couplings are assumed to be uniform, as the cycle grows to an infinite chain, we show that the distribution (under suitable dilation and translation) converges to a Kesten distribution.
Forward integration, convergence and non-adapted pointwise multipliers
Authors: Pronk Matthijs , Veraar Mark
Published: March 2015

In this paper we study the forward integral of operator-valued processes with respect to a cylindrical Brownian motion. In particular, we provide conditions under which the approximating sequence of processes of the forward integral, converges to the stochastic integral process with respect to Sobolev norms of smoothness α < 1/2. This result will be used to derive a new integration by parts formula for the forward integral.
NUMERICAL SIMULATION OF PRESSURE-INDUCED CELL PRINTING
Authors: ABEDINI HASSAN , MOVAHED SAEID , ABOLFATHI NABIOLLAH
Published: March 2015

Nowadays, because of great biomedical applications of state-of-the art prototyping (bio-printing), many studies have been conducted in this field with focus on three-dimensional prototyping. There are several mechanisms for bio-printing of live cells such as piezoelectric and thermal and pneumatic inkjeting systems. Cell viability should be preserved during the bio-printing process. Lots of researches have been carried out to investigate and compare cell viability through different prototyping mechanisms. In order to quantify percentage of the cells that are killed during the proto-typing process, applied stresses on the cell and consequently its deformation should be calculated. A maximum strain energy density that the cell can tolerate is reported in the range of 25 Kj ⋅ m-3 to 100 Kj ⋅ m-3. This can be considered as a criteria to find the percentage of the damaged cells during the bio-printing processes. In this study, the bio-printing of the cell has been modeled and the cell viability have been investigated. Firstly, it is shown that in modeling of the bio-printing process, the effects of dynamic flow on calculating the applied stress on the cell is not negligible and must be considered. In the next step, the percentage of damaged endothelial cell aggregate under 80 kPa applied pressure (64 MPa/m) and 200 micron nozzle diameter is reported. Based on findings of this study, the percentage of endothelial cells viability under mentioned condition is reported 76%. The proposed method of this study can be utilized to examine the cell viability and performance of each prototyping systems.
Acoustic Analysis of Condenser Fan of Split Air Conditioner Using Numerical and Experimental Method
Authors: Gulhane Nitin , Patil Sandip , Singh Kanwaljeet
Published: March 2015

The present work aims to investigate the accurate method of performing computational fluid dynamics (CFD) — Acoustic analysis for axial flow fans in split air conditioner system. A comprehensive simulation procedure is developed to predict flow-induced noise in a system. The three-dimensional domain using k–ε turbulence model and Ffowcs Williams and Hawkings (FW-H) acoustic model is considered to predict noise generated by the fan blade surface. The acoustic and flow performances of the fan are predicted simultaneously using a computational aero-acoustic technique (combining steady flow and noise propagation analysis). The different cases are simulated by varying the blade angle, blade depth, blade width and serrations at trailing edge of fan blade. An impact of each of these parameter on A-weighted sound pressure level (SPL) and mass flow rate at outlet is determined. The numeric value of obtained A-weighted SPL by CFD simulation is found to be in close agreement with the experimental result within 5.4%. Finally, above mentioned parameters are varied in simulation and optimized design is proposed based on A-weighted SPL and cubic feet per minute (CFM). All simulations are carried out in commercially available CFD solver; ANSYS FLUENT 13.
Resources Sequencing Using Automatic Prerequisite--Outcome Annotation
Authors: Changuel Sahar , Labroche Nicolas , Bouchon-Meunier Bernadette
Published: March 2015

The objective of any tutoring system is to provide resources to learners that are adapted to their current state of knowledge. With the availability of a large variety of online content and the disjunctive nature of results provided by traditional search engines, it becomes crucial to provide learners with adapted learning paths that propose a sequence of resources that match their learning objectives. In an ideal case, the sequence of documents provided to the learner should be such that each new document relies on concepts that have been already defined in previous documents. Thus, the problem of determining an effective learning path from a corpus of web documents depends on the accurate identification of outcome and prerequisite concepts in these documents and on their ordering according to this information. Until now, only a few works have been proposed to distinguish between prerequisite and outcome concepts, and to the best of our knowledge, no method has been introduced so far to benefit from this information to produce a meaningful learning path. To this aim, this article first describes a concept annotation method that relies on machine-learning techniques to predict the class of each concept—prerequisite or outcome—on the basis of contextual and local features. Then, this categorization is exploited to produce an automatic resource sequencing on the basis of different representations and scoring functions that transcribe the precedence relation between learning resources. Experiments conducted on a real dataset built from online resources show that our concept annotation approach outperforms the baseline method and that the learning paths automatically generated are consistent with the ground truth provided by the author of the online content.
A Sparse Projection and Low-Rank Recovery Framework for Handwriting Representation and Salient Stroke Feature Extraction
Authors: Zhang Zhao , Liu Cheng-Lin , Zhao Ming-Bo
Published: March 2015

In this article, we consider the problem of simultaneous low-rank recovery and sparse projection. More specifically, a new
Robust Principal Component Analysis
(RPCA)-based framework called
Sparse Projection and Low-Rank Recovery
(SPLRR) is proposed for handwriting representation and salient stroke feature extraction. In addition to achieving a low-rank component encoding principal features and identify errors or missing values from a given data matrix as RPCA, SPLRR also learns a similarity-preserving sparse projection for extracting salient stroke features and embedding new inputs for classification. These properties make SPLRR applicable for handwriting recognition and stroke correction and enable online computation. A cosine-similarity-style regularization term is incorporated into the SPLRR formulation for encoding the similarities of local handwriting features. The sparse projection and low-rank recovery are calculated from a convex minimization problem that can be efficiently solved in polynomial time. Besides, the supervised extension of SPLRR is also elaborated. The effectiveness of our SPLRR is examined by extensive handwritten digital repairing, stroke correction, and recognition based on benchmark problems. Compared with other related techniques, SPLRR delivers strong generalization capability and state-of-the-art performance for handwriting representation and recognition.
Modeling the Thermal Dynamics of Buildings
Authors: Ghosh Siddhartha , Reece Steve , Rogers Alex , Roberts Stephen , Malibari Areej , Jennings Nicholas R.
Published: March 2015

Minimizing the energy consumed by heating, ventilation, and air conditioning (HVAC) systems of residential buildings without impacting occupants’ comfort has been highlighted as an important artificial intelligence (AI) challenge. Typically, approaches that seek to address this challenge use a model that captures the thermal dynamics within a building, also referred to as a thermal model. Among thermal models, gray-box models are a popular choice for modeling the thermal dynamics of buildings. They combine knowledge of the physical structure of a building with various data-driven inputs and are accurate estimators of the state (internal temperature). However, existing gray-box models require a detailed specification of all the physical elements that can affect the thermal dynamics of a building a priori. This limits their applicability, particularly in residential buildings, where additional dynamics can be induced by human activities such as cooking, which contributes additional heat, or opening of windows, which leads to additional leakage of heat. Since the incidence of these additional dynamics is rarely known, their combined effects cannot readily be accommodated within existing models.

To overcome this limitation and improve the general applicability of gray-box models, we introduce a novel model, which we refer to as a latent force thermal model of the thermal dynamics of a building, or LFM-TM. Our model is derived from an existing gray-box thermal model, which is augmented with an extra term referred to as the learned residual. This term is capable of modeling the effect of any a priori unknown additional dynamic, which, if not captured, appears as a structure in a thermal model’s residual (the error induced by the model). More importantly, the learned residual can also capture the effects of physical elements such as a building’s envelope or the lags in a heating system, leading to a significant reduction in complexity compared to existing models.

To evaluate the performance of LFM-TM, we apply it to two independent data sources. The first is an established dataset, referred to as the FlexHouse data, which was previously used for evaluating the efficacy of existing gray-box models [Bacher and Madsen 2011]. The second dataset consists of heating data logged within homes located on the University of Southampton campus, which were specifically instrumented to collect data for our thermal modeling experiments. On both datasets, we show that LFM-TM outperforms existing models in its ability to accurately fit the observed data, generate accurate day-ahead internal temperature predictions, and explain a large amount of the variability in the future observations. This, along with the fact that we also use a corresponding efficient sequential inference scheme for LFM-TM, makes it an ideal candidate for model-based predictive control, where having accurate online predictions of internal temperatures is essential for high-quality solutions.
Combining Sketching and Traditional Diagram Editing Tools
Authors: Stapleton Gem , Plimmer Beryl , Delaney Aidan , Rodgers Peter
Published: March 2015

The least cognitively demanding way to create a diagram is to draw it with a pen. Yet there is also a need for more formal visualizations, that is, diagrams created using both traditional keyboard and mouse interaction. Our objective is to allow the creation of diagrams using traditional and stylus-based input. Having two diagram creation interfaces requires that changes to a diagram should be automatically rendered in the other visualization. Because sketches are imprecise, there is always the possibility that conversion between visualizations results in a lack of syntactic consistency between the two visualizations. We propose methods for converting diagrams between forms, checking them for equivalence, and rectifying inconsistencies. As a result of our theoretical contributions, we present an intelligent software system allowing users to create and edit diagrams in sketch or formal mode. Our proof-of-concept tool supports diagrams with connected and spatial syntactic elements. Two user studies show that this approach is viable and participants found the software easy to use. We conclude that supporting such diagram creation is now possible in practice.
On Discovery of Spatiotemporal Influence-Based Moving Clusters
Authors: Patel Dhaval
Published: March 2015

A moving object cluster is a set of objects that move close to each other for a long time interval. Existing works have utilized object trajectories to discover moving object clusters efficiently. In this article, we define a spatiotemporal influence-based moving cluster that captures spatiotemporal influence spread over a set of spatial objects. A spatiotemporal influence-based moving cluster is a sequence of spatial clusters, where each cluster is a set of nearby objects, such that each object in a cluster influences at least one object in the next immediate cluster and is also influenced by an object from the immediate preceding cluster. Real-life examples of spatiotemporal influence-based moving clusters include diffusion of infectious diseases and spread of innovative ideas. We study the discovery of spatiotemporal influence-based moving clusters in a database of spatiotemporal events. While the search space for discovering all spatiotemporal influence-based moving clusters is prohibitively huge, we design a method, STIMer, to efficiently retrieve the maximal answer. The algorithm STIMer adopts a top-down recursive refinement method to generate the maximal spatiotemporal influence-based moving clusters directly. Empirical studies on the real data as well as large synthetic data demonstrate the effectiveness and efficiency of our method.
Energy-Oriented Partial Desktop Virtual Machine Migration
Authors: Bila Nilton , Wright Eric J. , Lara Eyal De , Joshi Kaustubh , Lagar-Cavilla H. Andrés , Park Eunbyung , Goel Ashvin , Hiltunen Matti , Satyanarayanan Mahadev
Published: March 2015

Modern offices are crowded with personal computers. While studies have shown these to be idle most of the time, they remain powered, consuming up to 60% of their peak power. Hardware-based solutions engendered by PC vendors (e.g., low-power states, Wake-on-LAN) have proved unsuccessful because, in spite of user inactivity, these machines often need to remain network active in support of background applications that maintain network presence. Recent proposals have advocated the use of consolidation of idle desktop Virtual Machines (VMs). However, desktop VMs are often large, requiring gigabytes of memory. Consolidating such VMs creates large network transfers lasting in the order of minutes and utilizes server memory inefficiently. When multiple VMs migrate concurrently, networks become congested, and the resulting migration latencies are prohibitive. We present
partial VM migration,
an approach that transparently migrates only the working set of an idle VM. It creates a partial replica of the desktop VM on the consolidation server by copying only VM metadata, and it transfers pages to the server on-demand, as the VM accesses them. This approach places desktop PCs in low-power mode when inactive and switches them to running mode when pages are needed by the VM running on the consolidation server. To ensure that desktops save energy, we have developed sleep scheduling and prefetching algorithms, as well as the
context-aware selective resume
framework, a novel approach to reduce the latency of power mode transition operations in commodity PCs. Jettison, our software prototype of partial VM migration for off-the-shelf PCs, can deliver 44--91% energy savings during idle periods of at least 10 minutes, while providing low migration latencies of about 4 seconds and migrating minimal state that is under an order of magnitude of the VM’s memory footprint.
Motivation as a Lens to Understand Online Learners
Authors: Kizilcec René F. , Schneider Emily
Published: March 2015

Open online learning environments attract an audience with diverse motivations who interact with structured courses in several ways. To systematically describe the motivations of these learners, we developed the Online Learning Enrollment Intentions (OLEI) scale, a 13-item questionnaire derived from open-ended responses to capture learners' authentic perspectives. Although motivations varied across courses, we found that each motivation predicted key behavioral outcomes for learners (N = 71, 475 across 14 courses).

From learners' motivational and behavioral patterns, we infer a variety of needs that they seek to gratify by engaging with the courses, such as meeting new people and learning English. To meet these needs, we propose multiple design directions, including virtual social spaces outside any particular course, improved support for local groups of learners, and modularization to promote accessibility and organization of course content. Motivations thus provide a lens for understanding online learners and designing online courses to better support their needs.
Large-Scale Educational Campaigns
Authors: Liu Yun-En , Ballweber Christy , O'rourke Eleanor , Butler Eric , Thummaphan Phonraphee , Popović Zoran
Published: March 2015

Educational technology requires a delivery mechanism to scale. One method that has not yet seen widespread use is the educational campaign: large-scale, short-term events focused on a specific educational topic, such as the Hour of Code campaign. These are designed to generate media coverage and lend themselves nicely to collaborative or competitive goals, thus potentially leveraging social effects and community excitement to increase engagement and reach students who otherwise would not participate. In this article, we present a case study of three such campaigns that we ran to encourage students to play an algebra game—DragonBox Adaptive: the Washington, Norway, and Minnesota Algebra Challenges. We provide several design recommendations for future campaigns based on our experience, including the effects of different incentive schemes, the insertion of “tests” to fast-forward students to levels of appropriate difficulty, and the strengths and weaknesses of campaigns as a method of collecting experimental data.
Computer science curricula 2013 (CS2013)
Authors: Sahami Mehran
Published: March 2015

The ACM/IEEE-CS Computer Science Curricula 2013 (CS2013) report provides guidelines on undergraduate programs in computer science. The report includes a knowledge area on Intelligent Systems, which presents the topics and learning outcomes related to AI that are recommended for undergraduate CS programs to include.
Reinforcement learning and planning for preference balancing tasks
Authors: Faust Aleksandra
Published: March 2015

Many robotic motion tasks, such as UAV control, have non-linear and high-dimensional dynamics. Difficult for both human demonstration and explicit solutions, these tasks can be described with opposing preferences. This thesis develops PEARL, a real-time solution for such tasks on acceleration-controlled systems with unknown dynamics, and finds PEARL's safety conditions.
Long-term measurement of renal cortical and medullary tissue oxygenation and perfusion in unanesthetized sheep
Authors: Calzavacca Paolo , Evans Roger G. , Bailey Michael , Lankadeva Yugeesh R. , Bellomo Rinaldo , May Clive N.
Published: March 2015

The role of renal cortical and medullary hypoxia in the development of acute kidney injury is controversial, partly due to a lack of techniques for the long-term measurement of intrarenal oxygenation and perfusion in conscious animals. We have, therefore, developed a methodology to chronically implant combination probes to chronically measure renal cortical and medullary tissue perfusion and oxygen tension (tPo2) in conscious sheep and evaluated their responsiveness and reliability. A transit-time flow probe and a vascular occluder were surgically implanted on the left renal artery. At the same operation, dual fiber-optic probes, comprising a fluorescence optode to measure tPo2and a laser-Doppler probe to assess tissue perfusion, were inserted into the renal cortex and medulla. In recovered conscious sheep ( n = 8) breathing room air, mean 24-h cortical and medullary tPo2were similar (31.4 ± 0.6 and 29.7 ± 0.7 mmHg, respectively). In the renal cortex and medulla, a 20% reduction in renal blood flow (RBF) decreased perfusion (14.6 ± 8.6 and 41.2 ± 8.5%, respectively) and oxygenation (48.1 ± 8.5 and 72.4 ± 8.5%, respectively), with greater decreases during a 50% reduction in RBF. At autopsy, minimal fibrosis was observed around the probes. In summary, we have developed a technique to chronically implant fiber-optic probes in the renal cortex and medulla for recording tissue perfusion and oxygenation over many days. In normal resting conscious sheep, cortical and medullary tPo2were similar. The responses to and recovery from renal artery occlusion, together with the consistent measurements over a 24-h period, demonstrate the responsiveness and stability of the probes.
P-Chloroaniline Poisoning Causing Methemoglobinemia: A Case Report and Review of the Literature
Authors: Messmer Anna Sarah , Nickel Christian Hans , Bareiss Dirk
Published: March 2015

Background. Methemoglobin (MetHb) most commonly results from exposure to an oxidizing chemical but may also arise from genetic, dietary, or even idiopathic etiologies.P-chloroaniline (PCA) was one of the first substances described in the context of acquired methemoglobinemia.Case Report. We report the case of a cyanotic chemistry worker who presented to our emergency department (ED) after working with PCA. His peripheral oxygen saturation (SpO2) measured by pulse oximetry was at 81% and remained on that level despite oxygen administration (100% oxygenation via nonrebreather mask). His MetHb level was measured at 42.8% in arterial blood gas analysis. After treatment with intravenous methylene blue cyanosis resolved and the patient was discharged after 36 hours of observation.Conclusion. Acquired methemoglobinemia is a treatable condition, which may cause significant morbidity and mortality. The knowledge about the most common causes, fast diagnostic, and proper treatment is crucial.
Antifungal Activity of Coumarin Mammeisin Isolated from Species of theKielmeyeraGenre (Family: Clusiaceae or Guttiferae)
Authors: Marcondes Helcio Cassemiro , de Oliveira Tânia T. , Taylor Jason G. , Hamoy Moisés , do Leonel Neto Arman , de Mello Vanessa Joia , Nagem Tanus J.
Published: March 2015

Coumarin mammeisin isolated fromKielmeyera elatawas evaluated for its toxicity and antifungal activities. The toxicity of mammeisin was investigated by utilizing theArtemia salinamethodology to determine its LD50value. The minimum inhibitory concentration (MIC) of fungiCandidasp. was assessed for mammeisin, presenting equivalent activity to ketoconazole but displaying better results than fluconazole.
Video Superresolution Reconstruction Using Iterative Back Projection with Critical-Point Filters Based Image Matching
Authors: Zhang Yixiong , Tao Mingliang , Yang Kewei , Deng Zhenmiao
Published: March 2015

To improve the spatial resolution of reconstructed images/videos, this paper proposes a Superresolution (SR) reconstruction algorithm based on iterative back projection. In the proposed algorithm, image matching using critical-point filters (CPF) is employed to improve the accuracy of image registration. First, a sliding window is used to segment the video sequence. CPF based image matching is then performed between frames in the window to obtain pixel-level motion fields. Finally, high-resolution (HR) frames are reconstructed based on the motion fields using iterative back projection (IBP) algorithm. The CPF based registration algorithm can adapt to various types of motions in real video scenes. Experimental results demonstrate that, compared to optical flow based image matching with IBP algorithm, subjective quality improvement and an average PSNR score of 0.53 dB improvement are obtained by the proposed algorithm, when applied to video sequence.
The Role of Kenya Meteorological Service in Weather Early Warning in Kenya
Authors: Shilenje Zablon W. , Ogwang Bob A.
Published: March 2015

Early warning in weather forecasting entails provision of timely and effective weather information that allows individuals, organisations, or communities exposed to likely weather hazards to take action that avoids or reduces their exposure to risks. Various sectors have developed different ways to mitigate the effects of climate anomalies. The study reviews the existing monitoring and response structures, and communications flow channels of weather data at different levels, focusing on the role of Kenya Meteorological Service (KMS). The methodology employed was literature review of various documents. The study argues that early warning and weather information communication are essential elements for effective governance of weather risks through a well-developed warning system. At the end, the study recommends strengthening the existing structures with respect to weather monitoring, processing, and dissemination of weather products to end users.