bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced production of bacterial cellulose by using a biofilm reactor and its material property analysis
Authors: Cheng Kuan-Chen , Catchmark Jeff M , Demirci Ali
Published: July 2009

Bacterial cellulose has been used in the food industry for applications such as low-calorie desserts, salads, and fabricated foods. It has also been used in the paper manufacturing industry to enhance paper strength, the electronics industry in acoustic diaphragms for audio speakers, the pharmaceutical industry as filtration membranes, and in the medical field as wound dressing and artificial skin material. In this study, different types of plastic composite support (PCS) were implemented separately within a fermentation medium in order to enhance bacterial cellulose (BC) production by Acetobacter xylinum. The optimal composition of nutritious compounds in PCS was chosen based on the amount of BC produced. The selected PCS was implemented within a bioreactor to examine the effects on BC production in a batch fermentation. The produced BC was analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Among thirteen types of PCS, the type SFYR+ was selected as solid support for BC production by A. xylinum in a batch biofilm reactor due to its high nitrogen content, moderate nitrogen leaching rate, and sufficient biomass attached on PCS. The PCS biofilm reactor yielded BC production (7.05 g/L) that was 2.5-fold greater than the control (2.82 g/L). The XRD results indicated that the PCS-grown BC exhibited higher crystallinity (93%) and similar crystal size (5.2 nm) to the control. FESEM results showed the attachment of A. xylinum on PCS, producing an interweaving BC product. TGA results demonstrated that PCS-grown BC had about 95% water retention ability, which was lower than BC produced within suspended-cell reactor. PCS-grown BC also exhibited higher T
max compared to the control. Finally, DMA results showed that BC from the PCS biofilm reactor increased its mechanical property values, i.e., stress at break and Young's modulus when compared to the control BC. The results clearly demonstrated that implementation of PCS within agitated fermentation enhanced BC production and improved its mechanical properties and thermal stability.
Accelerating epistasis analysis in human genetics with consumer graphics hardware
Authors: Sinnott-Armstrong Nicholas A , Greene Casey S , Cancare Fabio , Moore Jason H
Published: July 2009

Background

Human geneticists are now capable of measuring more than one million DNA sequence variations from across the human genome. The new challenge is to develop computationally feasible methods capable of analyzing these data for associations with common human disease, particularly in the context of epistasis. Epistasis describes the situation where multiple genes interact in a complex non-linear manner to determine an individual's disease risk and is thought to be ubiquitous for common diseases. Multifactor Dimensionality Reduction (MDR) is an algorithm capable of detecting epistasis. An exhaustive analysis with MDR is often computationally expensive, particularly for high order interactions. This challenge has previously been met with parallel computation and expensive hardware. The option we examine here exploits commodity hardware designed for computer graphics. In modern computers Graphics Processing Units (GPUs) have more memory bandwidth and computational capability than Central Processing Units (CPUs) and are well suited to this problem. Advances in the video game industry have led to an economy of scale creating a situation where these powerful components are readily available at very low cost. Here we implement and evaluate the performance of the MDR algorithm on GPUs. Of primary interest are the time required for an epistasis analysis and the price to performance ratio of available solutions.

Findings

We found that using MDR on GPUs consistently increased performance per machine over both a feature rich Java software package and a C cluster implementation. The performance of a GPU workstation running a GPU implementation reduces computation time by a factor of 160 compared to an 8-core workstation running the Java implementation on CPUs. This GPU workstation performs similarly to 150 cores running an optimized implementation on a Beowulf cluster. Furthermore this GPU system provides extremely cost effective performance while leaving the CPU available for other tasks. The GPU workstation containing three GPUs costs $2000 while obtaining similar performance on a Beowulf cluster requires 150 CPU cores which, including the added infrastructure and support cost of the cluster system, cost approximately $82,500.

Conclusion

Graphics hardware based computing provides a cost effective means to perform genetic analysis of epistasis using MDR on large datasets without the infrastructure of a computing cluster.
Characters Lounge
Authors: Kunin Aaron
Published: July 2009

This essay defines character as a device that collects every example of a kind of person. This formalist definition derives from seventeenth-century books of characteristic writings. The essay tests this definition against the antiformalist one derived from the realist novel, in which the job of a character is to individuate. The comic rather than tragic historiography of the formalist account makes it slightly preferable to the antiformalist one. The essay's archive is intended to be comprehensive and includes representative examples from poems, novels, plays, comic books, and works of criticism.
Voltaire's Parrot; or, How to Do Things with Birds
Authors: DiPiero Thomas
Published: July 2009

Beginning in the mid-seventeenth century, thinkers in various disciplines evoked birds and other animals that appeared able to talk to make points about language use and human reason and identity. Talking birds initially allowed philosophers to draw parallels between language and the Cartesian model of human beings as both body and spirit, since language consisted of material sounds as vehicles for abstract ideas. By the eighteenth century the talking bird in literature had become a metaphor for a natural language that could express the truth in any and all circumstances. In later works of both literature and natural history, talking birds—and also monkeys—symbolized the point where thinking and material substances met. However, instead of offering a synthesis of those two substances, as the human does in Cartesian philosophy, talking animals highlighted a point of contention where thought and human identity were continuously and dynamically produced.
Hawthorne's Twisted Letters
Authors: Otten Thomas J.
Published: July 2009

Ekphrasis undergoes a decisive shift in Nathaniel Hawthorne and his contemporaries. Whereas Gotthold Ephraim Lessing and other seventeenth- and eighteenth-century writers (John Dryden, Alexander Pope) distinguished between verbal and visual arts through metaphors of realms and boundaries, Hawthorne twists the genres together again, as do John Keats and Robert Browning. Snakes in The Marble Faun, vines in The Blithedale Romance, and the A in The Scarlet Letter are tangled figures that at once image both the relationship between the genres and the newly powerful nature of relationships between persons. Similarly, the fullness and the insecurity of friendship are conveyed by verbal pictures that borrow a sense of plenitude from the visual arts even as they fail to achieve the direct presence of those media. An analysis of words and images in The Token, the gift book in which so many of Hawthorne's early tales first appeared, suggests that to read ekphrasis attentively in Hawthorne is to read the idiom of the interpersonal realm. Ekphrasis thus emerges not as a timeless figure to be cherished only by formalists but as a powerful tool for the historian, a moment that compresses into a single figure a culture's fictions of affiliation and estrangement.
Quality of Care in Single-Payer and Multipayer Health Systems
Authors: Feldman Roger
Published: July 2009

In this article, I argue that unregulated markets will not find the right level of health care quality but that at the same time it is not clear that single-payer systems will do any better. My perspective combines the economic theory of public goods and the institutional payment arrangements found in many single-payer systems. If, as I believe, health care quality is a public good, it will be underprovided in a multipayer system. Single-payer systems often allocate a fixed budget to health care professionals or administrators and give them considerable discretion in determining quality as well as quantity of service. With care being free or almost free at the point of use, patients will demand more services than administrators want to provide. The result is rationing by waiting—which should be present in all such systems and is present in most of them. I develop several implications of the theory and an agenda for future research on quality of care in single-payer and multipayer health systems.
Nkcc1 (Slc12a2) is required for the regulation of endolymph volume in the otic vesicle and swim bladder volume in the zebrafish larva
Authors: Abbas Leila , Whitfield Tanya T.
Published: July 2009

Endolymph is the specialised extracellular fluid present inside the inner ear. In mammals, disruptions to endolymph homeostasis can result in either collapse or distension of the endolymphatic compartment in the cochlea, with concomitant hearing loss. The zebrafish little ears (lte)mutant shows a collapse of the otic vesicle in the larva, apparently owing to a loss of endolymphatic fluid in the ear, together with an over-inflation of the swim bladder. Mutant larvae display signs of abnormal vestibular function by circling and swimming upside down. The two available alleles of lte are homozygous lethal: mutant larvae fail to thrive beyond 6 days post-fertilisation. Patterning of the otic vesicle is apparently normal. However, the expression of several genes thought to play a role in endolymph production is downregulated, including the sodium-potassium-chloride cotransporter gene nkcc1 (slc12a2) and several Na+/K+-ATPase channel subunit genes. We show here that lte mutations correspond to lesions in nkcc1. Each allele has a point mutation that disrupts splicing, leading to frame shifts in the coding region that predict the generation of truncated products. Endolymph collapse in the lte/nkcc1 mutant shows distinct parallels to that seen in mouse Nkcc1 mutants, validating zebrafish as a model for the study of endolymph disorders. The collapse in ear volume can be ameliorated in the to27d allele of lte by injection of a morpholino that blocks splicing at an ectopic site introduced by the mutation. This exemplifies the use of morpholinos as potential therapeutic agents for genetic disease.
Distinct functional specificities are associated with protein isoforms encoded by theDrosophiladorsal-ventral patterning genepipe
Authors: Zhang Zhenyu , Zhu Xianjun , Stevens Leslie M. , Stein David
Published: July 2009

Spatially regulated transcription of the pipe gene in ventral cells of the Drosophila ovary follicle cell epithelium is a key event that specifies progeny embryo dorsal-ventral (DV) polarity. pipeencodes ten putative protein isoforms, all of which exhibit similarity to vertebrate glycosaminoglycan-modifying enzymes. Expression of one of the isoforms, Pipe-ST2, in follicle cells has previously been shown to be essential for DV patterning. pipe is also expressed in the embryonic salivary gland and its expression there is required for normal viability. Here, we show that in addition to Pipe-ST2, seven of the other Pipe isoforms are expressed in the ovary, whereas all Pipe isoforms are abundantly expressed in the embryo. Of the ten isoforms, only Pipe-ST2 can restore ventral and lateral pattern elements to the progeny of otherwise pipe-null mutant females. By contrast, three Pipe isoforms, but not Pipe-ST2, support the production of a novel pipe-dependent epitope present in the embryonic salivary gland. These data indicate that differences in functional specificity, and presumably enzymatic specificity, are associated with several of the Pipe isoforms. In addition, we show that uniform expression of the Pipe-ST2 isoform in the follicle cell layer of females otherwise lacking pipe expression leads to the formation of embryos with a DV axis that is appropriately oriented with respect to the intrinsic polarity of the eggshell. This suggests the existence of a second mechanism that polarizes the Drosophila embryo, in addition to the ventrally restricted transcription of the pipe gene.
Conditional inactivation ofHas2reveals a crucial role for hyaluronan in skeletal growth, patterning, chondrocyte maturation and joint formation in the developing limb
Authors: Matsumoto Kazu , Li Yingcui , Jakuba Caroline , Sugiyama Yoshinori , Sayo Tetsuya , Okuno Misako , Dealy Caroline N. , Toole Bryan P. , Takeda Junji , Yamaguchi Yu , Kosher Robert A.
Published: July 2009

The glycosaminoglycan hyaluronan (HA) is a structural component of extracellular matrices and also interacts with cell surface receptors to directly influence cell behavior. To explore functions of HA in limb skeletal development, we conditionally inactivated the gene for HA synthase 2, Has2, in limb bud mesoderm using mice that harbor a floxed allele of Has2 and mice carrying a limb mesoderm-specific Prx1-Cretransgene. The skeletal elements of Has2-deficient limbs are severely shortened, indicating that HA is essential for normal longitudinal growth of all limb skeletal elements. Proximal phalanges are duplicated in Has2mutant limbs indicating an involvement of HA in patterning specific portions of the digits. The growth plates of Has2-deficient skeletal elements are severely abnormal and disorganized, with a decrease in the deposition of aggrecan in the matrix and a disruption in normal columnar cellular relationships. Furthermore, there is a striking reduction in the number of hypertrophic chondrocytes and in the expression domains of markers of hypertrophic differentiation in the mutant growth plates, indicating that HA is necessary for the normal progression of chondrocyte maturation. In addition, secondary ossification centers do not form in the central regions of Has2 mutant growth plates owing to a failure of hypertrophic differentiation. In addition to skeletal defects, the formation of synovial joint cavities is defective in Has2-deficient limbs. Taken together,our results demonstrate that HA has a crucial role in skeletal growth,patterning, chondrocyte maturation and synovial joint formation in the developing limb.
Performance assessment in the maternity pathway in Tuscany region
Authors: Nuti Sabina , Bonini Anna , Murante Anna Maria , Vainieri Milena
Published: July 2009

The paper describes the performance measurement system of the maternity pathway used in Tuscany by health care professionals, general managers and regional policy-makers. This system uses 19 indicators grouped in six dimensions: population's state of health; compliance with regional guidelines; efficiency and financial performance; clinical and health assessment; patient satisfaction; and employees' satisfaction. The results are represented on a spider diagram that summarizes the results on the different dimensions. The Tuscan performance measurement system of the maternity pathway has been used to identify best practice within, and their adoption throughout, the Tuscan public health care system.
Improving patient safety incident reporting systems by focusing upon feedback – lessons from English and Welsh trusts
Authors: Wallace Louise M , Spurgeon Peter , Benn Jonathan , Koutantji Maria , Vincent Charles
Published: July 2009

This paper describes practical implications and learning from a multi-method study of feedback from patient safety incident reporting systems. The study was performed using the Safety Action and Information Feedback from Incident Reporting model, a model of the requirements of the feedback element of a patient safety incident reporting and learning system, derived from a scoping review of research and expert advice from world leaders in safety in high-risk industries. We present the key findings of the studies conducted in the National Health Services (NHS) trusts in England and Wales in 2006. These were a survey completed by risk managers for 351 trusts in England and Wales, three case studies including interviews with staff concerning an example of good practice feedback and an audit of 90 trusts clinical risk staff newsletters. We draw on an Expert Workshop that included 71 experts from the NHS, from regulatory bodies in health care, Royal Colleges, Health and Safety Executive and safety agencies in health care and high-risk industries (commercial aviation, rail and maritime industries). We draw recommendations of enduring relevance to the UK NHS that can be used by trust staff to improve their systems. The recommendations will be of relevance in general terms to health services worldwide.
MicroRNAs with a nucleolar location
Authors: Ritland Politz Joan C. , Hogan Eric M. , Pederson Thoru
Published: July 2009

There is increasing evidence that noncoding RNAs play a functional role in the nucleus. We previously reported that the microRNA (miRNA), miR-206, is concentrated in the nucleolus of rat myoblasts, as well as in the cytoplasm as expected. Here we have extended this finding. We show by cell/nuclear fractionation followed by microarray analysis that a number of miRNAs can be detected within the nucleolus of rat myoblasts, some of which are significantly concentrated there. Pronounced nucleolar localization is a specific phenomenon since other miRNAs are present at only very low levels in the nucleolus and occur at much higher levels in the nucleoplasm and/or the cytoplasm. We have further characterized a subset of these miRNAs using RT-qPCR and in situ hybridization, and the results suggest that some miRNAs are present in the nucleolus in precursor form while others are present as mature species. Furthermore, we have found that these miRNAs are clustered in specific sites within the nucleolus that correspond to the classical granular component. One of these miRNAs is completely homologous to a portion of a snoRNA, suggesting that it may be processed from it. In contrast, the other nucleolar-concentrated miRNAs do not show homology with any annotated rat snoRNAs and thus appear to be present in the nucleolus for other reasons, such as modification/processing, or to play roles in the late stages of ribosome biosynthesis or in nonribosomal functions that have recently been ascribed to the granular component of the nucleolus.
Nanostructured oxides for energy storage applications in batteries and supercapacitors
Authors: Chandra Amreesh , Roberts Alexander J. , Lam How Yee Eric , Slade Robert C. T.
Published: July 2009

Nanostructured materials are extensively investigated for application in energy storage and power generation devices. This paper deals with the synthesis and characterization of nanomaterials based on oxides of vanadium and with their application as electrode materials for energy storage systems viz. supercapacitors. These nano-oxides have been synthesized using a hydrothermal route in the presence of templates: 1-hexadecylamine, Tweens and Brij types. Using templates during synthesis enables tailoring of the particle morphology and physical characteristics of synthesized powders. Broad X-ray diffraction peaks show the formation of nanoparticles, confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. SEM studies show that a large range of nanostructures such as needles, fibers, particles, etc. can be synthesized. These particles have varying surface areas and electrical conductivity. Enhancement of surface area as much as seven times relative to surface areas of starting parent materials has been observed. These properties make such materials ideal candidates for application as electrode materials in supercapacitors. Assembly and characterization of supercapacitors based on electrodes containing these active nano-oxides are discussed. Specific capacitance of >100 F g–1 has been observed. The specific capacitance decreases with cycling: causes of this phenomenon are presented.
Aerosol-generated mesoporous silicon oxycarbide particles
Authors: Pauletti Alberto , Moskowitz Guillaume , Millan Thomas , Fernández-Martín Cristina , Boissière Cédric , Gervais Christel , Babonneau Florence
Published: July 2009

Aerosol-generated mesoporous organosilica submicronic spheres have been converted into porous silicon oxycarbide (SiCO) glasses by pyrolysis at 1000 °C in an inert atmosphere. Spherical mesoporous particles obtained from acidic solutions of 1,2-bis(triethoxysilyl)ethane and Pluronic® F127 structuring agent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption/desorption, and multinuclear solid-state magic-angle spinning (MAS) NMR. These particles were then pyrolyzed at 1000 °C and transformed into a SiCO phase as evidenced by 29Si MAS NMR, while TEM shows preserved mesoporosity, unfortunately difficult to access owing to the presence of an outer layer of dense silica.
Relations between chemical changes and mechanical properties of thermally treated wood 10th EWLP, Stockholm, Sweden, August 25–28, 2008
Authors: Windeisen Elisabeth , Bächle Helmut , Zimmer Bernhard , Wegener Gerd
Published: July 2009

Thermal treatments of wood (Fagus sylvatica and Fraxinus excelsior) were examined. The temperature load on wood causes characteristic changes in the chemical composition, which were determined by means of several defined methods. The results confirm that in addition to the degradation of polyoses lignin, known as the thermally most stable compound, also shows significant thermal alterations. In addition, mechanical properties of the specimens were examined in order to correlate these results with the effects of chemical changes of thermally treated wood. It was shown, e.g., that the decomposition of the polyoses can affect the strength properties both positively and negatively.
A novel, mild and selective methylation of carboxyl groups in cellulosic pulps 10th EWLP, Stockholm, Sweden, August 25–28, 2008
Authors: Tot Ivana , Müller Yvonne , Werner Carsten , Rosenau Thomas , Potthast Antje
Published: July 2009

A method for selective, fast, and near-quantitative methylation of carboxyl groups in the presence of aliphatic hydroxyl groups of cellulose was developed. The main advantage of the method is the complete maintenance of cellulose integrity; no degradation of cellulose whatsoever during the methylation procedure was observed, making the protocol extremely useful in advanced cellulose analytics. Trimethylsilyl diazomethane (TMS-DAM) was used as the methylation agent. The methylation conditions were pre-optimized by means of carbohydrate model compounds with low-molecular weight, such as derivatives of glucuronic acid and hexenuronic acid, and then re-optimized for methylation of cellulose. The influence of reaction parameters, such as time, temperature, solvents, and concentration, was also determined. The reaction kinetics was monitored by fluorescence labeling of the remaining carboxyl groups according to the common FDAM protocol. A general protocol for the fast methylation of carboxyl groups in pulp samples is presented. The methylation with TMS-DAM is a very fast process, both in comparison to general heterogeneous reactions on cellulosic pulps, and especially in comparison to other methylation approaches. In dissolving and paper grade pulps, methylation of xylan carboxyls proceeded faster than methylation of cellulosic carboxyls. The methylation rate and kinetics are dependent on the pulp type. As application examples, electrokinetic measurements were used to demonstrate the “blocked” reactivity of carboxyl groups in spin-coated films of methylated pulp samples, and ICP-MS was used to demonstrate the drastically decreased metal ion binding capacity of pulp after such methylation.
Generalized Fitting Parameters of Three Permeability Functions for Predicting Water Coefficient of Permeability of Lateritic Soil
Authors: Gui Meen-Wah , Hsu Chun-Seng
Published: July 2009

The understanding of water flowing through unsaturated soil, such as in the upper layer of a residual hillside or earth dam, is particularly important for numerous geotechnical and geo-environmental problems. However, the effect of the water coefficient of permeability on flow of seepage through unsaturated soil, which is a function of void ratio and volumetric water content (or matric suction), is often ignored in engineering practice due to the requirements of a more advanced testing equipment and a longer testing duration for the determination of such a coefficient. A flexible-wall permeameter has been manufactured and used to determine the water coefficient of permeability of unsaturated lateritic soil under wetting condition. Three permeability functions have been evaluated and fitted to the laboratory measured results. From this, generalized fitting parameters, in terms of effective normal stress, of the three permeability functions have been derived for the study soil. The proposed generalized fitting parameters together with the permeability functions will provide practicing engineers with the essential parameter for the analysis of seepage related problems involving lateritic soil.
Evaluating Parameters for Characterization of Cracking in Asphalt Concrete
Authors: Tarefder Rafiqul A. , Kias Evan M. , Stormont John C.
Published: July 2009

This study evaluates parameters derived from laboratory tests to characterize crack initiation and propagation within the semi-circular asphalt concrete samples in the laboratory. Asphalt samples are compacted using a Superpave gyratory compactor, and then sliced and notched using a laboratory saw. The notch acts to facilitate crack initiation. Notched samples are subjected to a strain controlled compressive load in three point bending. Crack opening displacements (CODs) and loads are recorded in real time using four linear variable displacement transducers. Ultimate load, COD at ultimate load, cracking potential, fracture load, crack velocity, and slope of the crack propagation curve are determined from laboratory test results and evaluated for their suitability in characterizing crack initiation and crack propagation. In essence, these parameters are evaluated through examining the effects of notch tip location, moisture condition, and void ratio on crack initiation and propagation. It is shown that crack initiation can be best characterized by the ultimate load. Crack velocity and slope of the crack propagation curve show promise in characterizing crack propagation in the notched asphalt samples.
The ending of Sophocles’ Oedipus rex
Authors: Finglass Patrick J.
Published: July 2009

This article defends the authenticity of lines 1424–1523 of Sophocles’ Oedipus Rex in the face of a recent attack, and establishes that doubts about this section were first raised at the beginning of the eighteenth century.
Blood dosimetry from a single measurement of the whole body radioiodine retention in patients with differentiated thyroid carcinoma
Authors: Hänscheid Heribert , Lassmann Michael , Luster Markus , Kloos Richard T , Reiners Christoph
Published: July 2009

A simple method is presented to estimate the radiation-absorbed dose to the blood after radioiodine administration from a single external measurement of the whole-body retention in patients suffering from differentiated thyroid cancer. The blood dose is calculated applying the formalism of the Medical International Radiation Dose Committee under the assumptions that whole-body activity decays exponentially and that 14% of the whole-body residence time can be attributed to the blood. Accuracy and applicability of the method were tested based on data from 29 assessments, 18 pre-therapeutic tracer studies, and 11 ablation therapies, with whole-body and blood-retention measurements over at least 4 days. The mean of the absolute deviations between estimates and actual blood doses was found to be 14%, if external whole-body counting was performed on day 1 or 2 after radioiodine administration. This simple formalism is: 1) applicable to pre-therapeutic dosimetry for remnant ablation or treatment of metastases in a blood dose-based treatment concept and 2) applicable to blood-dose estimates after radioiodine therapy to determine radiation exposure. When combined with a measurement of the whole body retention 1 or 2 days after radioiodine administration this single time-point method closely approximates the classic, yet much more labor intensive multi-day dosimetry that measures both blood and whole-body activities.
Differential mortality drives life‐history evolution and population dynamics in the fish Brachyrhaphis rhabdophora
Authors: Johnson Jerald B. , Zúñiga-Vega J. Jaime
Published: July 2009

Life‐history theory predicts that populations experiencing different levels of extrinsic mortality will evolve divergent reproductive strategies. Previous work in the live‐bearing fish Brachyrhaphis rhabdophora shows that individuals from populations that occur with piscivorous fish mature earlier and at smaller sizes and have more and smaller offspring than fish from populations without predators. However, until now, there have been no data to demonstrate that differences in mortality rates actually exist between predator and predator‐free sites. Here we present the results of a serial mark–recapture field study designed to estimate mortality rates in natural populations of B. rhabodophora from Costa Rica. We found that fish from predator environments experience higher overall mortality rates and proportionally higher adult mortality rates than fish from predator‐free environments. We then ask what impact differences in mortality rates have on B. rhabdophora population dynamics. Using a population matrix modeling approach, we found that B. rhabdophora that co‐occur with predators have population growth rates similar to those without predators and both have confidence intervals that span λ = 1.0. However, elasticity analysis revealed that the most important life‐history stages for population growth in predator environments are found early in life and include growth through early ontogenetic stages and survival as small adults; in contrast, the most important life‐history stages for population growth in predator‐free environments occur late in life, including survival once large juvenile and adult stages are reached. Hence, we demonstrate two important links between predation and population demography, one ecological due to the direct impacts of predator‐induced mortality and the other expressed through predator‐mediated reproductive adaptation.
Nitrogen fixation in different biogeochemical niches along a 120 000‐year chronosequence in New Zealand
Authors: Menge Duncan N. L. , Hedin Lars O.
Published: July 2009

Biological nitrogen fixation (BNF) is the major nitrogen (N) input in many terrestrial ecosystems, yet we know little about the mechanisms and feedbacks that control this process in natural ecosystems. We here examine BNF in four taxonomically and ecologically different groups over the course of forest ecosystem development. At nine sites along the Franz Josef soil chronosequence (South Westland, New Zealand) that range in age from 7 to 120 000 yr old, we quantified BNF from the symbiotic plant Coriaria arborea, cyanolichens (primarily Pseudocyphellaria spp.), bryophytes (many species), and heterotrophic bacteria in leaf litter. We specifically examined whether these groups could act as “nitrostats” at the ecosystem level, turning BNF on when N is scarce (early in primary succession) and off when N is plentiful (later in succession and retrogression). Coriaria was abundant and actively fixing (∼11 kg N·ha−1·yr−1) in the youngest and most N‐poor site (7 yr old), consistent with nitrostat dynamics. Coriaria maintained high BNF rates independent of soil N availability, however, until it was excluded from the community after a single generation. We infer that Coriaria is an obligate N fixer and that the nitrostat feedback is mechanistically governed by species replacement at the community level, rather than down‐regulation of BNF at the physiological scale. Biological nitrogen fixation inputs from lichens (means of 0–2 kg N·ha−1·yr−1), bryophytes (0.7–10 kg N·ha−1·yr−1), and litter (1–2 kg N·ha−1·yr−1) were driven primarily by changes in density, which peaked at intermediate‐aged sites (and increased with soil N availability) for both lichens and bryophytes, and grew monotonically with soil age (but did not change with soil N) for litter. This non‐nitrostatic link between soil N availability and lichen/bryophyte BNF likely stems from increased tree biomass in more fertile sites, which increases epiphytic moisture conditions and habitable surface area. This apparent positive feedback could produce N‐rich conditions.
A simple parametric method for reducing sample sizes in gut passage time trials
Authors: Rawsthorne John , Roshier David A. , Murphy Sean R.
Published: July 2009

Seed dispersal is now regularly analyzed using spatially explicit models, relying in part on frugivore gut passage times to produce model outputs. In determining species‐specific gut passage times, there is a trade‐off in sample size between minimizing collection effort and maintaining statistical reliability. Here we demonstrate that a two‐parameter lognormal parametric distribution reliably fits empirical gut passage time distributions and is easily parameterized using relatively small data sets of approximately 30 defecations. We suggest this approach as a statistically reliable substitute for larger empirical gut passage data sets in seed dispersal modeling, and also as a way of using published gut passage data sets to parameterize new models.
Pollinator specialization and pollination syndromes of three related North AmericanSilene
Authors: Reynolds Richard J. , Westbrook M. Jody , Rohde Alexandra S. , Cridland Julie M. , Fenster Charles B. , Dudash Michele R.
Published: July 2009

Community and biogeographic surveys often conclude that plant–pollinator interactions are highly generalized. Thus, a central implication of the pollination syndrome concept, that floral trait evolution occurs primarily via specialized interactions of plants with their pollinators, has been questioned. However, broad surveys may not distinguish whether flower visitors are actual pollen vectors and hence lack power to assess the relationship between syndrome traits and the pollinators responsible for their evolution. Here we address whether the floral traits of three closely related hermaphroditicSilenespp. native to eastern North America (S. caroliniana,S. virginica, andS. stellata) correspond to predicted specialized pollination based on floral differences among the three species and the congruence of these floral features with recognized pollination syndromes. A nocturnal/diurnal pollinator exclusion experiment demonstrated that all threeSilenespp. have diurnal pollinators, and onlyS. stellatahas nocturnal pollinators. Multiyear studies of visitation rates demonstrated that large bees, hummingbirds, and nocturnal moths were the most frequent pollinators ofS. caroliniana,S. virginica, andS. stellata, respectively. Estimates of pollen grains deposited and removed per visit generally corroborated the visitation rate results for all three species. However, the relatively infrequent diurnal hawkmoth pollinators ofS. carolinianawere equally effective and more efficient than the most frequent large bee visitors. Pollinator importance (visitation × deposition) of each of the animal visitors to each species was estimated and demonstrated that in most years large bees and nocturnal moths were the most important pollinators ofS. carolinianaandS. stellata, respectively. By quantifying comprehensive aspects of the pollination process we determined thatS. virginicaandS. stellatawere specialized on hummingbirds and nocturnal moths, respectively, andS. carolinianawas the least specialized with diurnal hawkmoth and large bee pollinators. Compared across theSilenespecies, divergent floral character states are consistent with increasing the attraction and/or pollen transfer efficiency of their respective major pollinators, which suggests that the pollinators are past and/or contemporary selective agents for floral trait evolution in these threeSilenespecies. We conclude that the pollination syndrome concept allows us to effectively relate the functional significance of floral morphology to the major pollinators of theseSilenespecies.
Flight metabolic rate andPgigenotype influence butterfly dispersal rate in the field
Authors: Niitepõld Kristjan , Smith Alan D. , Osborne Juliet L. , Reynolds Don R. , Carreck Norman L. , Martin Andrew P. , Marden James H. , Ovaskainen Otso , Hanski Ilkka
Published: July 2009

Dispersal is a key life‐history trait, especially in species inhabiting fragmented landscapes. The process of dispersal is affected by a suite of morphological, physiological, and behavioral traits, all of which have a more or less complex genetic basis and are affected by the prevailing environmental conditions. To be able to identify genetic and phenotypic effects on dispersal, movements have to be recorded over relevant spatial and temporal scales. We used harmonic radar to track free‐flying Glanville fritillary butterflies (Melitaea cinxia) released in the field and reconstructed their flight tracks for several hours. Flight track lengths for individual butterflies ranged from tens of meters to several kilometers. Butterflies were most mobile at midday and in intermediate temperatures. Flight metabolic rate (MR), measured prior to the tracking, explained variation in mobility at all scales studied. One‐third of the variation in the distance moved in one hour could be attributed to variation in flight MR. Heterozygous individuals at a single nucleotide polymorphism in the phosphoglucose isomerase (Pgi) gene moved longer distances in the morning and at lower ambient temperatures than homozygous individuals. A similar genotype × temperature interaction was found to affect the metabolic rate. Our results establish connections from molecular variation in a single gene to flight physiology and movement behavior at the landscape level. These results indicate a fitness advantage to the heterozygous genotype in low temperatures and suggest a mechanism by which varying environmental conditions maintain genetic polymorphism in populations.
Reproductive timing and patterns of development for the damselfly Coenagrion puella in the field
Authors: Lowe Chris D. , Harvey Ian F. , Watts Phillip C. , Thompson David J.
Published: July 2009

By a combination of detailed behavioral observations and molecular genetic approaches we have assessed development time, timing of first maturity, and the extent of genetic structure through the flying season in a wild population of the damselfly Coenagrion puella in England. This work provides the first estimate of development time (egg to mature adult) in the field based on individual damselflies. Development time was significantly longer for females than males. In contrast to reported laboratory studies, there was no difference in development times between different female color morphs. Development time ranged between 347 and 396 days and was negatively correlated with egg‐laying date. As a result eggs laid early in one season reach adult maturity relatively late in the next; concurrently individuals developing from eggs laid late mature relatively early. We speculate that this pattern of development is a direct physiological response to seasonal environmental variation and results in reproductive synchrony within a population. Size, specifically hind wing length, declined with development time in males, but not in females. In one of the two years of the study there was evidence for weak clustering of related individuals during the reproductive season. This appeared to be the result of developmental synchronization within families: variance in timing of maturation was smaller in full‐sib families than in half‐sib families or randomly assigned unrelated groups.
Optimization of Osmotic Dehydration of Radish in Salt Solution Using Response Surface Methodology
Authors: Petchi Manivannan , Manivasagan Rajasimman
Published: July 2009

Response surface methodology was used to determine the optimum processing conditions that yield maximum water loss and weight reduction and minimum solid gain during osmotic dehydration of radish in salt solution. The experiments were conducted according to Central Composite Design (CCD). The independent process variables for osmotic dehydration process were temperature (25  45°C), processing time (30 -150 minutes), salt concentrations (5 - 25% w/w) and solution to sample ratio (5:1  25:1). The osmotic dehydration process was optimized for water loss, solid gain, and weight reduction. The optimum conditions were found to be: temperature  36°C, immersion time - 95 min, salt concentration  25% and solution to sample ratio 15:1. At this optimum point, water loss, solid gain and weight reduction were found to be 34.5 (g/100 g initial sample), 2.2 (g/100 g initial sample) and 32.1 (g/100 g initial sample), respectively.
Cultural and Family Challenges to Managing Type 2 Diabetes in Immigrant Chinese Americans
Authors: Chesla Catherine A. , Chun Kevin M. , Kwan Christine M.L.
Published: July 2009

OBJECTIVE

Although Asians demonstrate elevated levels of type 2 diabetes, little attention has been directed to their unique cultural beliefs and practices regarding diabetes. We describe cultural and family challenges to illness management in foreign-born Chinese American patients with type 2 diabetes and their spouses.

RESEARCH DESIGN AND METHODS

This was an interpretive comparative interview study with 20 foreign-born Chinese American couples (n = 40) living with type 2 diabetes. Multiple (six to seven) semistructured interviews with each couple in individual, group, and couple settings elicited beliefs about diabetes and narratives of care within the family and community. Interpretive narrative and thematic analysis were completed. A separate respondent group of 19 patients and spouses who met the inclusion criteria reviewed and confirmed the themes developed from the initial couples.

RESULTS

Cultural and family challenges to diabetes management within foreign-born Chinese American families included how 1) diabetes symptoms challenged family harmony, 2) dietary prescriptions challenged food beliefs and practices, and 3) disease management requirements challenged established family role responsibilities.

CONCLUSIONS

Culturally nuanced care with immigrant Chinese Americans requires attentiveness to the social context of disease management. Patients' and families' disease management decisions are seldom made independent of their concerns for family well-being, family face, and the reciprocal responsibilities required by varied family roles. Framing disease recommendations to include cultural concerns for balance and significant food rituals are warranted.
Clinical Interpretation of a Lower-Extremity Functional Scale–Derived Computerized Adaptive Test
Authors: Wang Ying-Chih , Hart Dennis L. , Stratford Paul W. , Mioduski Jerome E.
Published: July 2009

Background

The increasing use of computerized adaptive tests (CATs) to generate outcome measures during rehabilitation has prompted questions concerning score interpretation.

Objective

The purpose of this study was to describe meaningful interpretations of functional status (FS) outcome measures estimated with a body part–specific CAT developed from the Lower-Extremity Functional Scale (LEFS).

Design

This investigation was a prospective cohort study of 8,714 people who had hip impairments and were receiving physical therapy in 257 outpatient clinics in 31 states (United States) between January 2005 and June 2007.

Methods

Four approaches were used to clinically interpret outcome data. First, the standard error of the estimate was used to construct the 90% confidence interval for each CAT-generated score estimate. Second, percentile ranks were applied to FS scores. Third, 2 threshold approaches were used to define individual subject–level change: statistically reliable change and clinically important change. The fourth approach was a functional staging method.

Results

The precision of a single score was estimated from the FS score ±4. On the basis of the score distribution, 25th, 50th, and 75th percentile ranks corresponded to intake FS scores of 40, 48, and 59 and discharge FS scores of 50, 61, and 75, respectively. The reliable change index supported the conclusion that changes in FS scores of 7 or more units represented statistically reliable change, and receiver operating characteristic analyses supported the conclusion that changes in FS scores of 6 or more units represented minimal clinically important improvement. Participants were classified into 5 hierarchical levels of FS using a functional staging method.

Limitations

Because this study was a secondary analysis of prospectively collected data via a proprietary database management company, generalizability of results may be limited to participating clinics.

Conclusions

The results demonstrated how outcome measures generated from the hip LEFS CAT can be interpreted to improve clinical meaning. This finding might facilitate the use of patient-reported outcomes by clinicians during rehabilitation services.
Male Migration and the Lebanese Family
Authors: Khalaf Mona Chemali
Published: July 2009

This paper presents the preliminary results of a study that focuses on a micro aspect of Lebanese migration, i.e. the emigration of the head of the household and its impact on decision-making and well-being within the family, essentially on the wife left behind. For that purpose, a sample of 107 households was selected from a national survey covering 18,243 households conducted by Saint Joseph University in Beirut. After drawing the profiles of the households surveyed, this study uses four independent variables—the husband’s income, the length of the husband’s absence, the husband’s level of education, and the wife’s level of education—to assess the changes that have taken place. Despite the fact that the analysis of the data based on the selected sample can shed some light on the issues raised, this survey should be seen as an exploratory one that requires in-depth follow-up if sound correlations, conclusions, and recommendations are to be formulated.
Geographies of Lebanese Families
Authors: Joseph Suad
Published: July 2009

A new lexicon for studying families living across and between the borders of states and nations emerged in the past two decades, with “transnational families” as a dominant concept. This study challenges three of the key assumptions in the literature on transnational families by focusing on a case study of Lebanese families who have migrated to North America in the past decade. Ethnographic data on who wants to migrate, their identification with the nation, the nature of the family, and its geographical stakes suggest a need to rethink the transnational families literature on nationalism, bilocality and bifocality, and nuclearity. Presenting the case of five closely related and connected families from the same Christian village in the Metn region of Lebanon, the paper argues that their experiences offer new insights into the relationship between nation and family, and nation and women; situate women’s agency within these families; and reconfigure the meaning of deterritorialization.
Innovation and Re-orientation in Medical Education and Research: Challenges for Ibrahim Medical College
Authors: Anwar AJM Nurul , Fariduddin KM
Published: July 2009

doi: 10.3329/imcj.v1i1.2886Ibrahim Med. Coll. J. 2007; 1(1): i-ii