bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic PER repression mechanisms in the Drosophila circadian clock: from on-DNA to off-DNA
Authors: Menet Jerome S. , Abruzzi Katharine C. , Desrochers Jennifer , Rodriguez Joseph , Rosbash Michael
Published: February 2010

Transcriptional feedback loops are central to the generation and maintenance of circadian rhythms. In animal systems as well as Neurospora, transcriptional repression is believed to occur by catalytic post-translational events. We report here in the Drosophila model two different mechanisms by which the circadian repressor PERIOD (PER) inhibits CLOCK/CYCLE (CLK/CYC)-mediated transcription. First, PER is recruited to circadian promoters, which leads to the nighttime decrease of CLK/CYC activity. This decrease is proportional to PER levels on DNA, and PER recruitment probably occurs via CLK. Then CLK is released from DNA and sequestered in a strong, ∼1:1 PER–CLK off-DNA complex. The data indicate that the PER levels bound to CLK change dynamically and are important for repression, first on-DNA and then off-DNA. They also suggest that these mechanisms occur upstream of post-translational events, and that elements of this two-step mechanism likely apply to mammals.
Indications of ‘atopic bowel’ in patients with self‐reported food hypersensitivity
Authors: LILLESTØL K. , HELGELAND L. , ARSLAN LIED G. , FLORVAAG E. , VALEUR J. , LIND R. , BERSTAD A.
Published: February 2010

Aliment Pharmacol Ther 31, 1112–1122

Background  An association between atopic disease and gastrointestinal complaints has been suggested.

Aim  To explore the association between atopic disease, gastrointestinal symptoms, and possible gastrointestinal manifestations of atopic disease in patients with self‐reported food hypersensitivity.

Methods  Symptoms, skin prick tests, serum markers of allergy and intestinal permeability were recorded in 71 adult patients. Eosinophils, tryptase‐ and IgE‐positive cells were counted in duodenal biopsies.

Results  Sixty‐six (93%) patients had irritable bowel syndrome (IBS) and 43 (61%) had atopic disease, predominantly rhinoconjunctivitis. All 43 were sensitized to inhalant allergens, 29 (41%) to food allergens, but food challenges were negative. Serum total IgE and duodenal IgE‐positive cell counts were significantly correlated (P < 0.0001) and both were significantly higher in atopic than in non‐atopic patients (P < 0.0001 and P = 0.003 respectively). IgE‐positive cells appeared to be ‘armed’ mast cells. Intestinal permeability was significantly elevated in atopic compared with non‐atopic patients (P = 0.02). Gastrointestinal symptoms and numbers of tryptase‐positive mast cells and eosinophils did not differ between groups.

Conclusions  Patients with self‐reported food hypersensitivity had a high prevalence of IBS and atopic disease. Atopic patients had increased intestinal permeability and density of IgE‐bearing cells compared with non‐atopic patients, but gastrointestinal symptoms did not differ between groups.
Development of a synthetic plant volatile‐based attracticide for female noctuid moths. II. Bioassays of synthetic plant volatiles as attractants for the adults of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)
Authors: Gregg Peter C , Del Socorro Alice P , Henderson George S
Published: February 2010

This paper reports olfactometer studies to determine the attractiveness of synthetic equivalents of plant volatiles to Helicoverpa armigera (Hübner) moths. Synthetic volatiles identified from host plants and other volatiles reported in literature as attractants to various noctuid species were tested in a two‐choice olfactometer. Of 34 single chemicals tested, only seven were significantly attractive, and six were significantly repellent. However, when presented as blends of two or more volatiles, 21 of 31 blends tested were significantly attractive, and only one was significantly repellent. The most attractive blends were those containing four to six components, including aromatic volatiles primarily found in flowers, especially 2‐phenylethanol and phenylacetaldehyde and volatiles found primarily in leaves, including green leaf volatiles and terpenoids. Some general principles in blending volatiles for developing attracticides for H. armigera are presented, including the need for blend complexity, the combination of volatiles from leaves and flowers, and early consideration of pragmatic factors such as price and toxicological profile.
Paroster extraordinarius sp. nov., a new groundwater diving beetle from the Flinders Ranges, with notes on other diving beetles from gravels in South Australia (Coleoptera: Dytiscidae)
Authors: Leys Remko , Roudnew Ben , Watts Chris H S
Published: February 2010

The first groundwater (stygobitic) diving beetle is reported from South Australia. Paroster extraordinarius sp. nov. (Dytiscidae: Hydroporini) is described and figured. Its morphology and mitochondrial DNA sequences place it in the hydroporine genus Paroster Sharp. Phylogenetic analysis shows that the new species is imbedded in a clade of stygobitic species from the Yilgarn area of Western Australia. The evolution of this species is discussed and compared with observations on the behaviour and distribution of other dytiscid beetles found in subterranean habitats in South Australia.
Estimating Self‐Selection of Immigrants: Comparing Earnings Differentials Between Natives and Immigrants in the US and Israel
Authors: Haberfeld Yitchak
Published: February 2010

Immigrants’ economic assimilation in host countries is determined by patterns of self‐selection on both – observed attributes (mainly human capital) and unobserved attributes of the immigrants from their source countries. In the present study immigrants’ economic assimilation in the United States and Israel are compared. More specifically, the study compares the impact of immigrants’ unobserved characteristics on their earnings in both countries by applying a model for decomposing difference in differentials. It makes use of United States and Israeli decennial census data for comparing self‐selection patterns on unobserved attributes of Jewish immigrants from the former Soviet Union (FSU) who arrived in the United States and Israel during the 1970s. The results indicate that FSU immigrants who chose the United States have significantly higher levels of unobserved earnings determinants than those who chose Israel. These results are discussed in light of migration theories.
Radial data envelopment analysis models with mixed orientation of input and output
Authors: Wu Lifen , O'Brien Gregory C.
Published: February 2010

This paper discusses parametric solutions and envelopment formulations of radial data envelopment analysis (DEA) models with mixed orientation of input and output. These solutions geometrically but not numerically lie between the two usual solutions from input and output orientations. The consequent results provide alternative optimal solutions between those from input‐ and output‐oriented CCR models for constant returns to scale DEA models and optimal scale efficiency in addition to technical efficient solutions from input‐ and output‐oriented BCC models for variable returns to scale DEA models.
Buffer and server allocation in general multi‐server queueing networks
Authors: Van Woensel T. , Andriansyah R. , Cruz F. R. B. , Smith J. MacGregor , Kerbache L.
Published: February 2010

This paper deals with the joint optimization of the number of buffers and servers, an important issue since buffers and servers represent a significant amount of investment for many companies. The joint buffer and server optimization problem (BCAP) is a non‐linear optimization problem with integer decision variables. The performance of the BCAP is evaluated by a combination of a two‐moment approximation (developed for the performance analysis of finite general‐service queues) and the generalized expansion method (a well‐known method for performance analysis of acyclic networks of finite queues). A standard non‐linear optimization package is used to optimize the BCAP for a large number of experiments. A comprehensive set of numerical results is presented. The results show that the methodology is capable of handling the trade‐off between the number of servers and buffers, yielding better throughputs than previously published studies. Also, the importance of the squared coefficient of variation of the service time is stressed, since it strongly influences the approximate optimal allocation.
Annual planning of harvesting resources in the forest industry
Authors: Bredström David , Jönsson Petrus , Rönnqvist Mikael
Published: February 2010

A cost‐efficient use of harvesting resources is important in the forest industry. The main planning is carried out in an annual resource plan that is continuously revised. The harvesting operations are divided into harvesting and forwarding. The harvesting operation fells trees and puts them in piles in the harvest areas. The forwarding operation collects piles and moves them to storage locations adjacent to forest roads. These operations are conducted by machines (harvesters, forwarders and harwarders), and these are operated by crews living in cities/villages that are within some maximum distance from the harvest areas. Machines, harvest teams and harvest areas have different characteristics and properties and it is difficult to find the best possible match throughout the year. The aim of the planning is to find an annual plan with the lowest possible cost. The total cost is based on three parts: production cost, traveling cost and moving cost. The production cost is the cost for the harvesting and forwarding. The traveling cost is the cost for driving back and forwards (daily) from the home base to the harvest area and the moving cost is associated with moving the machines and equipment between harvest areas. The Forest Research Institute of Sweden (Skogforsk), together with a number of Swedish forest companies, has developed a decision support platform for the planning. One important element of this platform is that it should find high‐quality plans within short computational times. One central element is an optimization model that integrates the assignment of machines to harvest areas and schedules the harvest areas during the year for each machine. The problem is complex and we propose a two‐phase solution method where, first, we solve the assignment problem and, second, the scheduling. In order to be able to control the scheduling in phase 1 as well, we have introduced an extra cost component that controls the geographical distribution of harvest areas for each machine in phase 1. We have tested the solution approach on a case study from one of the larger Swedish forest companies. This case study involves 46 machines and 968 harvest areas representing a log volume of 1.33 million cubic meters. We describe some numerical results and experience from the development and tests.
Pharmacological Activation of IKr Impairs Conduction in Guinea Pig Hearts
Authors: LARSEN ANDERS PETER , OLESEN SØREN‐PETER , GRUNNET MORTEN , POELZING STEVEN
Published: February 2010

Activation of IKr Impairs Conduction.  Introduction: The hERG (Kv11.1) potassium channel underlies cardiac IKr and is important for cardiac repolarization. Recently, hERG agonists have emerged as potential antiarrhythmic drugs. As modulation of outward potassium currents has been suggested to modulate cardiac conduction, we tested the hypothesis that pharmacological activation of IKr results in impaired cardiac conduction.

Methods and Results: Cardiac conduction was assessed in Langendorff‐perfused guinea pig hearts. Application of the hERG agonist NS3623 (10 μM) prolonged the QRS rate dependently. A significant prolongation (16 ± 6%) was observed at short basic cycle length (BCL 90 ms) but not at longer cycle lengths (BCL 250 ms). The effect could be reversed by the IKr blocker E4031 (1 μM). While partial INa inhibition with flecainide (1 μM) alone prolonged the QRS (34 ± 3%, BCL 250 ms), the QRS was further prolonged by 19 ± 2% when NS3623 was added in the presence of flecainide. These data suggest that the effect of NS3623 was dependent on sodium channel availability. Surprisingly, in the presence of the voltage sensitive dye di‐4‐ANEPPS a similar potentiation of the effect of NS3623 was observed. With di‐4‐ANEPPS, NS3623 prolonged the QRS significantly (26 ± 4%, BCL 250 ms) compared to control with a corresponding decrease in conduction velocity.

Conclusion: Pharmacological activation of IKr by the hERG agonist NS3623 impairs cardiac conduction. The effect is dependent on sodium channel availability. These findings suggest a role for IKr in modulating cardiac conduction and may have implications for the use of hERG agonists as antiarrhythmic drugs. (J Cardiovasc Electrophysiol, Vol. 21, pp. 923‐929, August 2010)
Joint Variable Selection for Fixed and Random Effects in Linear Mixed‐Effects Models
Authors: Bondell Howard D. , Krishna Arun , Ghosh Sujit K.
Published: February 2010

SummaryIt is of great practical interest to simultaneously identify the important predictors that correspond to both the fixed and random effects components in a linear mixed‐effects (LME) model. Typical approaches perform selection separately on each of the fixed and random effect components. However, changing the structure of one set of effects can lead to different choices of variables for the other set of effects. We propose simultaneous selection of the fixed and random factors in an LME model using a modified Cholesky decomposition. Our method is based on a penalized joint log likelihood with an adaptive penalty for the selection and estimation of both the fixed and random effects. It performs model selection by allowing fixed effects or standard deviations of random effects to be exactly zero. A constrained expectation–maximization algorithm is then used to obtain the final estimates. It is further shown that the proposed penalized estimator enjoys the Oracle property, in that, asymptotically it performs as well as if the true model was known beforehand. We demonstrate the performance of our method based on a simulation study and a real data example.
Biclustering via Sparse Singular Value Decomposition
Authors: Lee Mihee , Shen Haipeng , Huang Jianhua Z. , Marron J. S.
Published: February 2010

SummarySparse singular value decomposition (SSVD) is proposed as a new exploratory analysis tool for biclustering or identifying interpretable row–column associations within high‐dimensional data matrices. SSVD seeks a low‐rank, checkerboard structured matrix approximation to data matrices. The desired checkerboard structure is achieved by forcing both the left‐ and right‐singular vectors to be sparse, that is, having many zero entries. By interpreting singular vectors as regression coefficient vectors for certain linear regressions, sparsity‐inducing regularization penalties are imposed to the least squares regression to produce sparse singular vectors. An efficient iterative algorithm is proposed for computing the sparse singular vectors, along with some discussion of penalty parameter selection. A lung cancer microarray dataset and a food nutrition dataset are used to illustrate SSVD as a biclustering method. SSVD is also compared with some existing biclustering methods using simulated datasets.
Treatment of longstanding groin pain in athletes: a systematic review
Authors: Jansen J. A. C. G. , Mens J. M. A. , Backx F. J. G. , Kolfschoten N. , Stam H. J.
Published: February 2010

The aims of this study were to determine (1) the kinds of treatments applied for longstanding groin pain (LGP) in athletes; (2) the results; and (3) the levels of evidence for the interventions. Digital databases P were searched for articles describing the effects of interventions for LGP in athletes. Treatment of LGP in athletes can consist of conservative measures such as rest or restricted activity, active or passive physical therapy, steroid injections or dextrose prolotherapy. Studies describing surgery generally mention failure of conservative measures, although a description of these conservative measures is mostly lacking. During surgery, a reinforcement of the abdominal wall is applied in most cases, using an open or laparoscopic approach. There is level I evidence that physical therapy aiming at strengthening and coordinating the muscles stabilizing hip and pelvis has superior results compared with passive physical therapy. For patients with a positive herniography and/or positive ilioinguinal or iliohypogastric nerve block tests, there are indications (level II) that surgery results in earlier return to sport compared with exercise therapy. Possibly, laparoscopic intervention might result in an earlier return to sport compared with open approach surgery (level III). For different clinical diagnoses, the same or similar surgical interventions were performed.
Tana River Mangabey Use of Nonforest Areas: Functional Connectivity in a Fragmented Landscape in Kenya
Authors: Wieczkowski Julie
Published: February 2010

Habitat loss and fragmentation is a serious threat to biodiversity. Fragment isolation can be reduced if fragments are connected, either structurally through habitat corridors or functionally if the species can move through the surrounding matrix. One‐way to evaluate landscape connectivity is to observe natural movements of animals within fragmented landscapes. The Tana River mangabey (Cercocebus galeritus) is an endangered monkey endemic to fragmented forests along the lower Tana River in Kenya, and who has been observed to move through matrix between fragments. One mangabey group moved through 1 km of matrix, while another group moved through two areas of matrix. I collected behavioral and ranging data on the latter group to describe its behavior and time spent in the matrix. Utilizing data from belt transects in the matrix and forest fragments, I characterized the vegetation structure of the matrix and compared it to the forests included in each group's home range. The group spent the majority of their time eating while in the matrix, and spent an average 36.4 min in one matrix area and 100 min in the other. The matrix is generally characterized by the highest measures for a nonforest attribute and the lowest measures for forest attributes. These results suggest that forest fragments are functionally, but not structurally, connected for the mangabey; a landscape approach to conservation, therefore, should be taken for the lower Tana River. Research investigating the limitations of the mangabey's ability to use the matrix is needed.
Biological Invasions in the Amazonian Tropical Rain Forest: The Case of Drosophilidae (Insecta, Diptera) in Ecuador, South America
Authors: Acurio Andrea , Rafael Violeta , Dangles Olivier
Published: February 2010

There have been few reports of invasions in continental rain forests, especially for exotic animals. This study provides original data concerning the potential of exotic drosophilid species to colonize the Amazonian tropical rain forest. To investigate if the structure of drosophilid assemblages differed in response to anthropogenic disturbance, we performed a taxonomic survey at six sites within the Yasuni National Park in Ecuadorian Amazonia along a disturbance gradient from pristine to clearcut artificial forest. A total of 7425 individuals from 34 species were collected of which seven species were exotic. There was significant variation in the assemblage composition along this disturbance gradient; 31 percent of which was explained by the presence of exotic species, particularly at the most disturbed sites, through nonmetric multidimensional scaling and SIMPER analyses. These results confirm the susceptibility of continental rain forests to invasion by exotic species. There is an urgent need to develop and implement monitoring systems, for example, based on drosophilid assemblage surveys, to detect exotic invasions in continental tropical forests.
Cloning and characterization of the gene encoding an ubiquitin‐activating enzyme E1 domain‐containing protein of silkworm,Bombyx mori
Authors: Wu Ping , Li Mu‐Wang , Jiang Yun‐Feng , Wang Zi‐Sheng , Guo Xi‐Jie
Published: February 2010

Abstract Bombyx moricytoplasmic polyhedrosis virus (BmCPV) is one of the major viral pathogens for the silkworm. To date, the molecular mechanism of BmCPV invasion has been unclear. We cloned the full length complementary (c)DNA which encodes the ubiquitin‐activating enzyme E1‐domain containing protein1 (UbE1DC1) ofBombyx moriby using suppression subtractive hybridization (SSH) and rapid amplification of complementary (c)DNA ends (RACE). The full‐length cDNA ofUbE1DC1gene is 1 919 bp, consisting of a 100 bp 5′ untranslated region, a 637 bp 3′ untranslated region and an 1 182 bp open reading frame (ORF), encoding a 393 amino acid protein. The protein contained the THiF_MoeB_hesA_family domain, an adenosine triphosphate binding site, which belongs to the family of ubiquitin‐activating enzyme E1. Reverse transcription – polymerase chain reaction analysis from the silkworm tissues, namely silk gland, hemocyte, fat body, gonad and midgut revealed thatUbE1DC1was expressed in all the five tissues. The real‐time quantitative polymerase chain reaction analysis indicated that the relative expression ofUbE1DC1in the normal midgut was approximately 9.78‐fold of that in the BmCPV‐infected midgut. It is implicated thatUbE1DC1may play an important role in the interaction between the host and BmCPV invasion.
Relative toxicity of three wheat herbicides to two species of Coccinellidae
Authors: Michaud J. P. , Vargas German
Published: February 2010

Abstract  On the High Plains of the USA, herbicides specific for broad‐leaf weeds are regularly applied to winter wheat in the early spring, sometimes late enough to coincide with the colonization of fields by cereal aphids and their natural enemies. We tested the toxicity of three such herbicides, Ally (Dupont), Rave (Syngenta) and 2,4‐D ester (generic), to neonate larvae of two coccinellid species important in cereal aphid biocontrol, Coleomegilla maculata DeGeer and Hippodamia convergens Guérin‐Méneville. Topical treatment of larvae with 2,4‐D resulted in 25% and 60% mortality in the two species, respectively, with surviving C. maculata larvae experiencing a 5% increase in developmental time. No significant effects were noted for the other two materials, save for a 2.5% increase in developmental time for C. maculata larvae exposed to Rave. No material caused significant mortality in either species when larvae were fed on prey (Schizaphis graminum Rondani) treated with herbicide 24 h earlier, although 2,4‐D reduced developmental time slightly in C. maculata. When herbicide applications are delayed enough in spring to coincide with aphid activity in wheat, farmers can reduce the risk of disrupting biological control by selecting an alternative to 2,4‐D.
Central role of the brain in stress and adaptation: Links to socioeconomic status, health, and disease
Authors: McEwen Bruce S. , Gianaros Peter J.
Published: February 2010

The brain is the key organ of stress reactivity, coping, and recovery processes. Within the brain, a distributed neural circuitry determines what is threatening and thus stressful to the individual. Instrumental brain systems of this circuitry include the hippocampus, amygdala, and areas of the prefrontal cortex. Together, these systems regulate physiological and behavioral stress processes, which can be adaptive in the short‐term and maladaptive in the long‐term. Importantly, such stress processes arise from bidirectional patterns of communication between the brain and the autonomic, cardiovascular, and immune systems via neural and endocrine mechanisms underpinning cognition, experience, and behavior. In one respect, these bidirectional stress mechanisms are protective in that they promote short‐term adaptation (allostasis). In another respect, however, these stress mechanisms can lead to a long‐term dysregulation of allostasis in that they promote maladaptive wear‐and‐tear on the body and brain under chronically stressful conditions (allostatic load), compromising stress resiliency and health. This review focuses specifically on the links between stress‐related processes embedded within the social environment and embodied within the brain, which is viewed as the central mediator and target of allostasis and allostatic load.
Multiple risk exposure as a potential explanatory mechanism for the socioeconomic status–health gradient
Authors: Evans Gary W. , Kim Pilyoung
Published: February 2010

The social patterning of disease and mortality provokes a search for explanation. One potential underlying explanation for socioeconomic status (SES) gradients in health is exposure to multiple risk factors. Income and class tend to sort individuals into different settings that are often accompanied by systematic differences in environmental quality. Housing and neighborhood quality, pollutants and toxins, crowding and congestion, and noise exposure all vary with SES. Persons lower in SES also experience more adverse interpersonal relationships with family members, friends, supervisors, and community members. Furthermore, exposure to these multiple risk factors is associated with worse health outcomes. Thus, the convergence of exposure to multiple physical and psychosocial risk factors accompanying disadvantage may account for a portion of SES gradients in health in both childhood and adulthood.
Treatment of Anemia With Darbepoetin Alfa in Heart Failure
Authors: Abraham William T. , Anand Inder S. , Klapholz Marc , Ponikowski Piotr , Scarlata Debra , Wasserman Scott M. , Van Veldhuisen Dirk J.
Published: February 2010

Anemia is common in heart failure (HF) patients. A prespecified pooled analysis of 2 randomized, double‐blind, placebo‐controlled studies evaluated darbepoetin alfa (DA) in 475 anemic patients with HF (hemoglobin [Hb], 9.0–12.5 g/dL). DA was administered subcutaneously every 2 weeks and titrated to achieve and maintain a target Hb level of 14.0±1.0 g/dL. By week 27, mean (SD) Hb concentrations did not increase with placebo but increased with DA from 11.5 (0.7) to 13.3 (1.3) g/dL. Hazard ratios (HRs) for DA compared with placebo for all‐cause death or first HF hospitalization (composite end point), all‐cause death, and HF hospitalization by month 12 were 0.67 (95% confidence interval [CI], 0.44–1.03; P=.067), 0.76 (95% CI, 0.39–1.48; P=.419), and 0.66 (95% CI, 0.40–1.07; P=.093), respectively. Incidence of adverse events was similar in both groups. In post hoc analyses, improvement in the composite end point was significantly associated with the mean Hb change from baseline (adjusted HR, 0.40; P=.017) with DA treatment. There was no increased risk of all‐cause mortality or first HF hospitalization with DA in patients with reduced renal function or elevated baseline B‐type natriuretic peptide, a biomarker of worse HF. These results suggest that DA is well tolerated, corrects HF‐associated anemia, and may have favorable effects on clinical outcomes.  Congest Heart Fail. 2010;16:87–95. © 2010 Wiley Periodicals, Inc.
Recasting Leadership Development
Authors: McCall Morgan W.
Published: February 2010

To the extent that leadership is learned, it is learned through experience. This article begins with seven conclusions about the role of experience in leadership development, ponders the reasons that what is known is so rarely applied, suggests some ways to put experience at the center of leadership development efforts, and concludes with a series of recommendations for practice and for future research.
Concentrations of unbound bevacizumab in the aqueous of untreated fellow eyes after a single intravitreal injection in humans
Authors: Meyer Carsten H. , Krohne Tim U. , Holz Frank G.
Published: February 2010

Purpose:  To determine the concentration of unbound bevacizumab in untreated fellow eyes after contralateral intravitreal injection of bevacizumab.

Methods:  A total of 18 eyes received intravitreal injections of 1.5 mg bevacizumab. Nine probes were obtained in the injected eye and nine in the fellow eye. Each group contained three individual eyes. Aqueous humour samples were obtained during uneventful phacoemulsification at three intervals 1–7 days (group a), 8–12 days (group b) or 13–28 days (group c).

Results:  In untreated fellow eyes, the concentration of unbound bevacizumab was below the detectable limit of the ELISA (5 ng/ml in all samples). The mean concentration of unbound bevacizumab in the injected eye declined from 28.6 μg/ml (group a), 16.5 μg/ml (group b) to 7.4 μg/ml (group c).

Conclusions:  There are no pharmacological indications for a significant concentration of unbound bevacizumab in the anterior chamber of contralateral eyes in humans.
Study of clinical applications and safety for Pascal® laser photocoagulation in retinal vascular disorders
Authors: Muqit Mahiul M.K. , Sanghvi Chintan , McLauchlan Rita , Delgado Christine , Young Lorna B. , Charles Stephen J. , Marcellino George R. , Stanga Paulo E.
Published: February 2010

Purpose:  To establish safe laser parameter standards for 10–30 ms Pascal® laser in clinical practice and to evaluate clinical and visual outcomes using this 532‐nm multi‐spot photocoagulation system.

Methods:  Retrospective observational case series of 313 patients treated between 2006 and 2008. Evaluation of eight groups: A – panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR); B – focal laser treatment for clinically significant diabetic macular oedema; C – grid laser for diffuse diabetic macular oedema; D – sector PRP for ischaemic branch retinal vein occlusions (I‐BRVO); E – full PRP for ischaemic central retinal vein occlusions (I‐CRVO); F – macular laser treatment for macular oedema secondary to non‐ischaemic BRVO; G – full PRP for rubeosis iridis and/or neovascular glaucoma (NVG) secondary to I‐BRVO, I – CRVO or PDR; H – laser retinopexy for retinal breaks/degenerations.

Results:  Mean LogMAR visual acuity for all procedures improved postlaser (p = 0.065), and laser prevented visual loss in 85% eyes. Topical anaesthesia was only required. At mean follow‐up of 5 months, 72% procedures had a successful clinical outcome. Significantly higher powers were required for PRP using Pascal® compared to conventional laser (p = 0.001) in PDR, I‐BRVO, I‐CRVO and NVG. Sixty‐seven per cent of patients (15/20) were successfully treated with single‐session 20‐ms PRP using a mean 1952 burns. There were no laser‐associated adverse effects or ocular complications associated with multi‐spot PRP or macular Pascal® arrays.

Conclusions:  The clinical efficacy using 10‐ to 30‐ms pulse duration Pascal® laser is comparable to conventional standard protocols used for the treatment of vascular retinal disorders. Higher power, 10‐ to 30‐ms pulse duration laser may be safely and effectively used in clinical practice.
Strain‐dependent differences in electrogenic secretion of electrolytes across mouse colon epithelium
Authors: Flores Carlos A. , Cid L. Pablo , Sepúlveda Francisco V.
Published: February 2010

Mice have proven to be powerful models for the study of human physiology and pathophysiology. With the advent of techniques for genomic manipulation, the possibilities for studying inherited diseases in this convenient laboratory mammal are increasing by the day. It has been reported that when knocking out or otherwise modifying genes of interest in mice, the phenotype obtained can vary markedly depending on the genetic background of the animals used in the study. The aim of this work was to study whether the genetic background can influence the characteristics of fluid and electrolyte transepithelial transport in the distal colon of three mouse strains most in use in our and other laboratories. Ussing chamber recordings revealed that the colons of C57Bl/6J, Sv 129 and Black Swiss animals have distinctive responses to the calcium agonists carbachol and histamine that are not explained by the presence of different types of muscarinic and histaminergic receptors in these tissues. We have also found differences in the cAMP‐activated, KCNMA1‐channel‐dependent potassium secretion between the strains. We interpret this to indicate a unique distribution of KCNMA1 channels in lower parts of the crypt of Sv 129 colonic epithelium compared with that of C57Bl/6J and Black Swiss animals. The reported differences should be taken into account when choosing the genetic background of animals to be used for genetic modification.
Galvanize Your Class! Build a Battery of Students
Authors: Morse Robert A.
Published: February 2010

An inexpensive and simple class participation demonstration uses students, short lengths of metal pipe, and an inexpensive digital voltmeter to make a battery of students. Data taken illustrate the combination of emfs in series and parallel. This apparatus was awarded second place and a low-cost award in the 2007 AAPT Apparatus Competition.
Propelling Extended Objects
Authors: Humbert Richard
Published: February 2010

A force acting on just part of an extended object (either a solid or a volume of a liquid) can cause all of it to move. That motion is due to the transmission of the force through the object by its material. This paper discusses how the force is distributed to all of the object by a gradient of stress or pressure in it, which creates the local force that directly propels each part of the object. Those gradients resemble the ones created in objects by their weights. An example of the latter is the compressive stress in a column of a building increasing steadily toward its lower end. That gradient occurs because each horizontal section through the column supports all of the weight above it, including the load force pushing down on the column's upper end. The gradient resembles the pressure in a container of liquid increasing with depth in it. Likewise, the weight of a vertically hanging cable causes its tension and tensile stress to increase toward its upper end.
Short Note on Units: Planetary Units
Authors: Huggins Elisha
Published: February 2010

While the emphasis on SI units in introductory physics textbooks has mercifully eliminated the use of English units, the exclusion of other systems of units is not necessary. For years physicists have simplified calculations by doing things like setting ℏ = c = 1. We could not imagine putting 4πε0 into the formulas for Bohr orbits.1
Quantum Dotting the “i” of Inquiry: A Guided Inquiry Approach to Teaching Nanotechnology
Authors: Laubach Timothy A. , Elizondo Lee A. , McCann Patrick J. , Gilani Shahryar
Published: February 2010

When illuminating four “mystery” vials of nanoparticle solution with a 405-nm light emitting diode (LED), four distinct colors related to the peak wavelength of fluorescent emission can be observed.1 This phenomenon perplexes high school physics students and leads to the subsequent exploratory question, “Why are the four vials emitting a different color light if they all contain the same material and are illuminated with the same light source?” That question gives students the opportunity to collect and analyze data, which leads to the development of the inherent scientific concept that the color of the emitted light depends on the size of the material (quantum dot) suspended in solution.
Measuring Air Density in the Introductory Lab
Authors: Calzà G. , Gratton L. M. , López-Arias T. , Oss S.
Published: February 2010

The measurement of the mass, or the density, of air can easily be done with very simple materials and offers many interesting phenomena for discussion—buoyancy and its effects being the most obvious but not the only one. Many interesting considerations can be done regarding the behavior of gases, the effect of the external conditions in the measurement, and the reason for the choice of the procedure, among others. One of the most widespread approaches makes use of rubber balloons. Such an approach can be misleading if attention is not paid to the effect of the buoyant force on the balloon, exerted by the surrounding air. Air is weightless in an environment full of it. While this fact can usually be neglected in daily, nontechnical weight measurements, it is not the case when we are interested in the weight of air itself. A sketch such as the one depicted in Fig. 1 is often presented in elementary science textbooks, as a demonstration that air has weight. A search of the Internet will reveal that this misleading approach is often presented as the simplest one for this kind of measurement at an elementary level1 and represents one among other common misconceptions that can be found in K-6 science textbooks as discussed, for instance, in Ref. 2. For a more detailed description of the flaws inherent to the measurement of air's weight with a rubber balloon, see Ref. 3. In this paper we will describe two procedures to measure the density of air: weighing a PET bottle and a vacuum rigid container. There are other interesting ways to estimate the weight of air; see, for instance, the experiment of Zhu and Se-yuen using carbon dioxide and Archimedes' principle.4 We emphasize the experimental implications and the physical reasons for the accuracy and conceptual correctness of each method. It is important not to undervalue the importance of both simplicity and reliability for any experimental measurement made in a didactic context.
Jasmonate Biochemical Pathway
Authors: Gfeller Aurélie , Dubugnon Lucie , Liechti Robin , Farmer Edward E.
Published: February 2010

Jasmonates are potent physiological and developmental regulators synthesized from fatty acid precursors.
Supporting views in data stream management systems
Authors: Ghanem Thanaa M. , Elmagarmid Ahmed K. , Larson Per-Åke , Aref Walid G.
Published: February 2010

In relational database management systems, views supplement basic query constructs to cope with the demand for “higher-level” views of data. Moreover, in traditional query optimization, answering a query using a set of existing materialized views can yield a more efficient query execution plan. Due to their effectiveness, views are attractive to data stream management systems. In order to support views over streams, a data stream management system should employ a closed (or composable) continuous query language. A closed query language is a language in which query inputs and outputs are interpreted in the same way, hence allowing query composition.

This article introduces the Synchronized SQL (or SyncSQL) query language that defines a data stream as a sequence of modify operations against a relation. SyncSQL enables query composition through the unified interpretation of query inputs and outputs. An important issue in continuous queries over data streams is the frequency by which the answer gets refreshed and the conditions that trigger the refresh. Coarser periodic refresh requirements are typically expressed as sliding windows. In this article, the sliding window approach is generalized by introducing the synchronization principle that empowers SyncSQL with a formal mechanism to express queries with arbitrary refresh conditions. After introducing the semantics and syntax, we lay the algebraic foundation for SyncSQL and propose a query-matching algorithm for deciding containment of SyncSQL expressions. Then, the article introduces the Nile-SyncSQL prototype to support SyncSQL queries. Nile-SyncSQL employs a pipelined incremental evaluation paradigm in which the query pipeline consists of a set of differential operators. A cost model is developed to estimate the cost of SyncSQL query execution pipelines and to choose the best execution plan from a set of different plans for the same query. An experimental study is conducted to evaluate the performance of Nile-SyncSQL. The experimental results illustrate the effectiveness of Nile-SyncSQL and the significant performance gains when views are enabled in data stream management systems.
Analyses of multi-level and multi-component compressed bitmap indexes
Authors: Wu Kesheng , Shoshani Arie , Stockinger Kurt
Published: February 2010

Bitmap indexes are known as the most effective indexing methods for range queries on append-only data, and many different bitmap indexes have been proposed in the research literature. However, only two of the simplest ones are used in commercial products. To better understand the benefits offered by the more sophisticated variations, we conduct an analytical comparison of well-known bitmap indexes, most of which are in the class of multi-component bitmap indexes. Our analysis is the first to fully incorporate the effects of compression on their performance. We produce closed-form formulas for both the index sizes and the query processing costs for the worst cases. One surprising finding is that the two simple indexes are in fact the best among multi-component indexes. Additionally, we investigate a number of novel variations in a class of multi-level indexes, and find that they answer queries faster than the best of multi-component indexes. More specifically, some two-level indexes are predicted by analyses and verified with experiments to be 5 to 10 times faster than well-known indexes. Furthermore, these two-level indexes have the optimal computational complexity for answering queries.
Server selection in large-scale video-on-demand systems
Authors: Carlsson Niklas , Eager Derek L.
Published: February 2010

Video on demand, particularly with user-generated content, is emerging as one of the most bandwidth-intensive applications on the Internet. Owing to content control and other issues, some video-on-demand systems attempt to prevent downloading and peer-to-peer content delivery. Instead, such systems rely on server replication, such as via third-party content distribution networks, to support video streaming (or pseudostreaming) to their clients. A major issue with such systems is the cost of the required server resources.

By synchronizing the video streams for clients that make closely spaced requests for the same video from the same server, server costs (such as for retrieval of the video data from disk) can be amortized over multiple requests. A fundamental trade-off then arises, however, with respect to server selection. Network delivery cost is minimized by selecting the
nearest
server, while server cost is minimized by directing closely spaced requests for the same video to a
common
server.

This article compares classes of server selection policies within the context of a simple system model. We conclude that: (i) server selection using dynamic system state information (rather than only proximities and average loads) can yield large improvements in performance, (ii) deferring server selection for a request as late as possible (i.e., until just before streaming is to begin) can yield additional large improvements, and (iii) within the class of policies using dynamic state information and deferred selection, policies using only “local” (rather than global) request information are able to achieve most of the potential performance gains.
Real-time H.264 video encoding in software with fast mode decision and dynamic complexity control
Authors: Ivanov Yuri V. , Bleakley C. J.
Published: February 2010

This article presents a novel real-time algorithm for reducing and dynamically controlling the computational complexity of an H.264 video encoder implemented in software. A fast mode decision algorithm, based on a Pareto-optimal macroblock classification scheme, is combined with a dynamic complexity control algorithm that adjusts the MB class decisions such that a constant frame rate is achieved. The average coding efficiency of the proposed algorithm was found to be similar to that of conventional encoding operating at half the frame rate. The proposed algorithm was found to provide lower average bitrate and distortion than static complexity scaling.
Using an internet based process to assess student art skills
Authors: Westman Hans
Published: February 2010

Methods for assessment have become increasingly important in education, especially in regards to complying with accreditation guidelines. The question is, how can this be done effectively at a school whose core curriculum focuses on teaching art? For a department that teaches courses through both campus and online modalities, a web-driven process has become an effective tool, allowing campus and online students to be reviewed side by side by both campus and online faculty alike.
Optical Spectroscopy for Noninvasive Monitoring of Stem Cell Differentiation
Authors: Downes Andrew , Mouras Rabah , Elfick Alistair
Published: February 2010

There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and coherent anti-Stokes Raman scattering (CARS) microscopy. These techniques are briefly described, and the ability of each to distinguish undifferentiated from differentiated cells is discussed. FTIR spectroscopy has demonstrated its ability to distinguish between stem cells and their derivatives. Raman spectroscopy shows a clear reduction in DNA and RNA concentrations during embryonic stem cell differentiation (agreeing with the well-known reduction in the nucleus to cytoplasm ratio) and also shows clear increases in mineral content during differentiation of mesenchymal stem cells. CARS microscopy can map these DNA, RNA, and mineral concentrations at high speed, and Mutliplex CARS spectroscopy/microscopy is highlighted as the technique with most promise for future applications.
Strong Convergence of Iterative Schemes for Zeros of Accretive Operators in Reflexive Banach Spaces
Authors: Jung JongSoo
Published: February 2010

We introduce composite iterative schemes by the viscosity iteration method for finding a zero of an accretive operator in reflexive Banach spaces. Then, under certain differen control conditions, we establish strong convergence theorems on the composite iterative schemes. The main theorems improve and develop the recent corresponding results of Aoyama et al. (2007), Chen and Zhu (2006, 2008), Jung (2010), Kim and Xu (2005), Qin and Su (2007) and Xu (2006) as well as Benavides et al. (2003), Kamimura and Takahashi (2000), Maingé (2006), and Nakajo (2006).
Robotic Monitoring of Gravitationally Lensed Quasars
Authors: Goicoechea Luis J. , Shalyapin Vyacheslav N. , Ullán Aurora
Published: February 2010

We report on the first observational phase of the Liverpool Quasar Lens Monitoring (LQLM) project. This mainly consisted of the optical follow‐up of three lensed quasars using the 2 m Liverpool Robotic Telescope. The observational subprogram started in January 2005 and was completed in July 2007. We also describe our photometric approaches (including two pipelines to extract accurate and reliable fluxes of images of lensed quasars), the performance of the telescope when taking modest nightly exposures of lens systems, and the main scientific results from the observed light curves. The LQLM archive and the current status of the project (second phase) are also outlined.