bluuebunny/crossref_metadata_2025 huggingface dataset:
Succession, climate and neighbourhood dynamics influence tree growth over time: an 87‐year record of change in aPinus resinosa‐dominated forest, Minnesota,USA
Authors: Curzon Miranda T. , D'Amato Anthony W. , Fraver Shawn , Huff Emily S. , Palik Brian J.
Published: September 2016

Question

Resource availability and its influence on tree‐to‐tree interactions are expected to change over the course of forest stand development, but the rarity of long‐term data sets has limited examinations of neighbourhood crowding over extended time periods. How do a history of neighbourhood interactions and population‐level dynamics, including demographic transition, impact long‐term tree growth?

Location

Natural maturePinus resinosa‐dominated forest in northern Minnesota,USA.

Methods

Using a spatially explicit data set of repeated diameter measurements recorded over an 87‐yr period, we modelled the influence of tree‐to‐tree interactions on growth as it varied over time. We also applied maximum likelihood estimation and simulated annealing to examine how inter‐ and intraspecific competition and the relative importance of neighbour size and distance varied over time and with different climatic conditions.

Results

Crowding had a consistent negative influence on growth, but crowding intensity and importance were dynamic over time and differed between trees that survived the entire study period compared to those that ultimately died. The scaling of neighbour diameter, neighbour distance, and neighbour species (inter‐ vs intraspecific competition) also varied as demographic transition occurred and longer‐lived species assumed greater dominance.

Conclusions

Given observed relationships with moisture stress (based on precipitation: potential evapotranspiration) and maximum temperature, crowding intensity and importance may increase if temperatures rise in the future and water become more limiting. Long‐term data sets, such as the record examined in this study, have immense value for testing assumptions about stand dynamics, particularly as forests respond to projected shifts in climate and disturbance regimes.
Attitudes to justice in a rural community
Authors: Newman Daniel
Published: September 2016

This paper offers a timely investigation into access to justice in rural areas through place-based research. The paper reports an empirical study designed to gain the local knowledge and personal experience of one particular group of rural dwellers in the hope that it might help encourage a wider discussion on access to rural justice. The research has been conducted within the wider socio-political context of austerity that provides a challenge to public-sector service delivery in general, alongside the particular legal impact of budget cuts on the provision of justice, with closures of large amounts of courts, the decline in legal aid provision and reductions in police numbers. Such are important issues for England and Wales as a whole, meaning that this research is contemporary and represents one of the first academic studies to specifically deal with the impact of austerity on access to justice. The value of this research is further heightened with its focus on the specific rural impact of such cuts as rural areas are those likely to face the biggest effect on provision while concomitantly being the least studied area of legal provision, with notably little scholarship in the past two decades into justice in rural England and Wales. Considering the damage these cuts may cause to rural justice is a current issue of utmost importance to the principle of access to justice. The paper offers the foundations upon which a new wave of academic attention to justice in rural areas should be developed, reflecting the need to give due credence to the rural in contemporary socio-legal scholarship.
Ocean currents determine functional connectivity in an Antarctic deep‐sea shrimp
Authors: Dambach Johannes , Raupach Michael J. , Leese Florian , Schwarzer Julia , Engler Jan O.
Published: September 2016

The coherency among larval stages of marine taxa, ocean currents and population connectivity is still subject to discussion. A common view is that organisms with pelagic larval stages have higher dispersal abilities and therefore show a relatively homogeneous population genetic structure. Contrary to this, local genetic differentiation is assumed for many benthic direct developers. Specific larval or adult migratory behavior and hydrographic effects may significantly influence distribution patterns, rather than passive drifting abilities alone. The Southern Ocean is an ideal environment to test for the effects of ocean currents on population connectivity as it is characterized by several well‐defined and strong isolating current systems. In this study we studied the genetic structure of the decapod deep‐sea shrimp Nematocarcinus lanceopes, which has planktotrophic larval stages. We analysed 194 individuals from different sample localities around the Antarctic continent using nine microsatellite markers. Consistent with a previous study based on mitochondrial DNA markers, primarily weak genetic patterns among N. lanceopes populations around the continent were found. Using ocean resistance modeling approaches we were able to show that subtle genetic differences among populations are more likely explained by ocean currents rather than by geographic distance for the Atlantic Sector of the Southern Ocean.
Copepod assemblages in a highly dynamic equatorial estuary on the Brazilian Amazon Coast
Authors: Atique Priscila , da Costa Kelli G. , Monteiro Marcela C. , Pereira Luci C. C. , da Costa Rauquírio M.
Published: September 2016

This study describes the spatial and temporal dynamics of the copepod fauna in the estuary of the Caeté River, a highly dynamic environment characterized by a unique set of hydrological and hydrodynamic attributes. This ecosystem is part of the Amazon Coastal Zone (ACZ), which sustains one of the world's largest continuous tracts of mangrove forest. In the present study, a predominance of high‐energy conditions characterized by macrotides and strong tidal currents was observed throughout the year. Salinity (0.03 ± 0.05–40.00 ± 0.84) and temperatures (26.43 ± 0.10–30.08 ± 0.43 °C) were higher than during the rainy season at all sampling stations. The highest chl‐a concentration (3.92 ± 1.47–17.63 ± 2.60 mg·m−3) was recorded at the most oligohaline (innermost) station during the rainy season, while no spatial or seasonal pattern was found in dissolved nutrient concentrations, except for phosphates, which exhibited the highest concentrations during the dry season. A total of 22 copepod taxa was identified, of which the most abundant were Oithona hebes, Oithona oswaldocruzi, Acartia tonsa, Paracalanus quasimodo, Euterpina acutifrons and Pseudodiaptomus marshi. Copepodites and nauplii were also recorded. Mean total copepod abundance varied from 710.73 ± 897 individuals (ind.)·m−3 at the inner station to 236,486 ± 398,360 ind.·m−3 near the mouth of the estuary (outermost station). The results reflected rainfall‐influenced oscillations in hydrological variables, mainly salinity, which determined shifts in the distribution of copepods and their community structure within the study area. This pattern may be typical of estuaries in the ACZ with similar hydrodynamic and hydrological attributes that are not influenced by the Amazon River plume.
Rapid invertebrate responses to macroalgal wrack: two novel field experiments on intertidal mudflats in Southern Australia
Authors: O'Brien Allyson L. , Morris Liz , Keough Michael J.
Published: September 2016

Macroalgal wrack deposition along coasts is highly variable but it plays an important role in the structure and function of marine communities. To date, most research has focused on the effects of decomposing wrack as it assimilates into the system but little is known about the immediate effects of wrack when it is first deposited in the habitat. Freshly deposited wrack may either wash away after a short period (1–2 days) or remain in the habitat and decay depending on tide and weather conditions. To understand the effects of this dynamic resource we experimentally manipulated wrack deposits on intertidal mudflats in Port Phillip Bay, Victoria, Australia. We conducted two experiments using defaunated patches of wrack (300 g wet weight) that were a mixture of seagrass and macroalgae and measured community responses after 2 days. The first experiment included real and artificial wrack patches to differentiate between taxa that responded to the biological and physical structure of the wrack. The second experiment used multiple wrack patches to investigate responses to a focal wrack patch that was surrounded by varying numbers of wrack additional patches (0, 2 or 4 × 300 g wet weight of wrack). Overall, wrack increased abundances of invertebrates and changed their distributions throughout the wrack and underlying sediment habitat. Mechanisms responsible for immediate taxa responses to the wrack related to the physical structure in the habitat and not biological attributes associated with the real patches. Ostracods and leptostracans were the exception to these patterns with colonization only occurring in real wrack and not the artificial wrack. In the multiple patch experiment the majority of the fauna moved vertically into the wrack from the bare sediment and not between surrounding patches of wrack. We suggest that specific characteristics, such as invertebrate mobility, feeding mode and sensitivity to changes in sediment condition, are important factors that influence individual taxa and overall community responses. Understanding the interactive effects of these characteristics with the characteristics of the wrack (magnitude, frequency, spatial arrangement and composition) is the key to developing predictive models that will inform the management of wrack in marine coastal habitats.
The last bastion? X chromosome genotyping of Anopheles gambiae species pair males from a hybrid zone reveals complex recombination within the major candidate ‘genomic island of speciation’
Authors: Caputo Beniamino , Pichler Verena , Mancini Emiliano , Pombi Marco , Vicente José L. , Dinis Joao , Steen Keith , Petrarca Vincenzo , Rodrigues Amabelia , Pinto Joao , della Torre Alessandra , Weetman David
Published: September 2016

Speciation with gene flow may be aided by reduced recombination helping to build linkage between genes involved in the early stages of reproductive isolation. Reduced recombination on chromosome X has been implicated in speciation within the Anopheles gambiae complex, species of which represent the major Afrotropical malaria vectors. The most recently diverged, morphologically indistinguishable, species pair, A. gambiae and Anopheles coluzzii, ubiquitously displays a ‘genomic island of divergence’ spanning over 4 Mb from chromosome X centromere, which represents a particularly promising candidate region for reproductive isolation genes, in addition to containing the diagnostic markers used to distinguish the species. Very low recombination makes the island intractable for experimental recombination studies, but an extreme hybrid zone in Guinea Bissau offers the opportunity for natural investigation of X‐island recombination. SNP analysis of chromosome X hemizygous males revealed: (i) strong divergence in the X‐island despite a lack of autosomal divergence; (ii) individuals with multiple‐recombinant genotypes, including likely double crossovers and localized gene conversion; (iii) recombination‐driven discontinuity both within and between the molecular species markers, suggesting that the utility of the diagnostics is undermined under high hybridization. The largely, but incompletely protected nature of the X centromeric genomic island is consistent with a primary candidate area for accumulation of adaptive variants driving speciation with gene flow, while permitting some selective shuffling and removal of genetic variation.
Convergence in organ size but not energy metabolism enzyme activities among wild Lake Whitefish (Coregonus clupeaformis) species pairs
Authors: Dalziel Anne C. , Laporte Martin , Rougeux Clément , Guderley Helga , Bernatchez Louis
Published: September 2016

The repeated evolution of similar phenotypes by similar mechanisms can be indicative of local adaptation, constraints or biases in the evolutionary process. Little is known about the incidence of physiological convergence in natural populations, so here we test whether energy metabolism in ‘dwarf’ and ‘normal’ Lake Whitefish evolves by similar mechanisms. Prior genomic and transcriptomic studies have found that divergence in energy metabolism is key to local adaptation in whitefish species pairs, but that distinct genetic and transcriptomic changes often underlie phenotypic evolution among lakes. Here, we predicted that traits at higher levels of biological organization, including the activities of energy metabolism enzymes (the product of enzyme concentration and turnover rate) and the relative proportions of metabolically active tissues (heart, liver, skeletal muscle), would show greater convergence than genetic and transcriptomic variation. We compared four whitefish species pairs and found convergence in organ size whereby all dwarf whitefish populations have a higher proportion of red skeletal muscle, three have relatively larger livers and two have relatively larger ventricles than normal fish. On the other hand, hepatic and muscle enzyme activities showed little convergence and were largely dependent on lake of origin. Only the most genetically divergent species pair (Cliff Lake) displayed white muscle enzyme activities matching results from laboratory‐reared normal and dwarf whitefish. Overall, these data show convergence in the evolution of organ size, but not in the activities of candidate enzymes of energy metabolism, which may have evolved mainly as a consequence of demographic or ecological differences among lakes.
Change in soil fungal community structure driven by a decline in ectomycorrhizal fungi following a mountain pine beetle (Dendroctonus ponderosae) outbreak
Authors: Pec Gregory J. , Karst Justine , Taylor D. Lee , Cigan Paul W. , Erbilgin Nadir , Cooke Janice E. K. , Simard Suzanne W. , Cahill James F.
Published: September 2016

Western North American landscapes are rapidly being transformed by forest die‐off caused by mountain pine beetle (Dendroctonus ponderosae), with implications for plant and soil communities. The mechanisms that drive changes in soil community structure, particularly for the highly prevalent ectomycorrhizal fungi in pine forests, are complex and intertwined. Critical to enhancing understanding will be disentangling the relative importance of host tree mortality from changes in soil chemistry following tree death.

Here, we used a recent bark beetle outbreak in lodgepole pine (Pinus contorta) forests of western Canada to test whether the effects of tree mortality altered the richness and composition of belowground fungal communities, including ectomycorrhizal and saprotrophic fungi. We also determined the effects of environmental factors (i.e. soil nutrients, moisture, and phenolics) and geographical distance, both of which can influence the richness and composition of soil fungi.

The richness of both groups of soil fungi declined and the overall composition was altered by beetle‐induced tree mortality. Soil nutrients, soil phenolics and geographical distance influenced the community structure of soil fungi; however, the relative importance of these factors differed between ectomycorrhizal and saprotrophic fungi. The independent effects of tree mortality, soil phenolics and geographical distance influenced the community composition of ectomycorrhizal fungi, while the community composition of saprotrophic fungi was weakly but significantly correlated with the geographical distance of plots.

Taken together, our results indicate that both deterministic and stochastic processes structure soil fungal communities following landscape‐scale insect outbreaks and reflect the independent roles tree mortality, soil chemistry and geographical distance play in regulating the community composition of soil fungi.
An auxin maximum in the middle layer controls stamen development and pollen maturation in Arabidopsis
Authors: Cecchetti Valentina , Celebrin Daniela , Napoli Nadia , Ghelli Roberta , Brunetti Patrizia , Costantino Paolo , Cardarelli Maura
Published: September 2016

Here, we investigated the role of auxin distribution in controlling Arabidopsis thaliana late stamen development.

We analysed auxin distribution in anthers by monitoring DR5 activity: at different flower developmental stages; inhibiting auxin transport; in the rpk2‐3 and ems1 mutants devoid of middle layer (ML) or tapetum, respectively; and in the auxin biosynthesis yuc6 and perception afb1‐3 mutants. We ran a phenotypic, DR5::GUS and gene expression analysis of yuc6rpk2 and afb1rpk2 double mutants, and of 1‐N‐naphthylphthalamic acid (NPA)‐treated flower buds.

We show that an auxin maximum, caused by transport from the tapetum, is established in the ML at the inception of late stamen development. rpk2‐3 mutant stamens lacking the ML have an altered auxin distribution with excessive accumulation in adjacent tissues, causing non‐functional pollen grains, indehiscent anthers and reduced filament length; the expression of genes controlling stamen development is also altered in rpk2‐3 as well as in NPA‐treated flower buds. By decreasing auxin biosynthesis or perception in the rpk2‐3 background, we eliminated these developmental and gene expression anomalies.

We propose that the auxin maximum in the ML plays a key role in late stamen development, as it ensures correct and coordinated pollen maturation, anther dehiscence and filament elongation.
Importance of mixotrophic bacterivory can be predicted by light and loss rates
Authors: Fischer Robert , Giebel Helge‐Ansgar , Hillebrand Helmut , Ptacnik Robert
Published: September 2016

Recent observational studies form oligotrophic waters provide ample evidence that mixotrophic flagellates often account for the bulk of bacterivory. However, we lack a general framework that allows a mechanistic understanding of success of mixotrophs in the competition with heterotrophic bacterivores. This is especially needed for integrating mixotrophy in models of the microbial loop. Based on general tradeoffs linked to the combined resource use in mixotrophs (generalist versus specialist), we propose a concept where mixotrophs are favored by conditions of high light – low losses, corresponding to the situation found in the surface waters of oligotrophic oceans. Under such conditions, they can achieve positive net growth at very low resource levels, allowing simultaneous competition with specialized protists. Conversely, heterotrophic bacterivores and photoautotrophs should be especially favored in more productive and low‐light conditions. We show experimentally that the combined effect of light and loss rates (dilution) predicts the success of mixotrophic bacterivorous flagellates. Moreover, our results suggest that total bacterivory, contrary as seen in the traditional microbial loop concept, has a more intricate coupling to light.
Radionuclide Assessment of Cardiac Function and Dyssynchrony in Children with Idiopathic Ventricular Tachycardia
Authors: ZAVADOVSKY KONSTANTIN V. , SAUSHKIN VICTOR V. , KHLYNIN MIKHAIL S. , POPOV SERGEY V. , LISHMANOV YURI B.
Published: September 2016

Background

The aim of the study was to evaluate the impact of idiopathic ventricular tachycardia and premature ventricular beats on cardiac function and dyssynchrony and to elucidate relationships between data of scintigraphic and intracardiac electrophysiology studies (EPSs).

Methods

The study comprised 64 patients with idiopathic ventricular arrhythmias (VAs; median age of 14 years ranging from 8 to 18 years). The control group comprised 20 patients (median age of 12 ranging from 7 to 16 years) without cardiac arrhythmias. EPS and radiofrequency ablation (RFA) procedure for VA were performed in 21 children according to indications. The functional state of both ventricles was assessed by gated blood pool single photon emission computer tomography (GBP‐SPECT) before and after RFA in all patients.

Results

Patients with VA had local areas of asynchronous myocardial contraction (AMC). Compared with the control group, VA patients had significantly higher values of end‐diastolic volume, end‐systolic volume, and lower contractility indices. Negative association was found between total numbers of AMC areas and cardiac contractility indices. Ectopic foci localization, determined based on EPS data, was associated with AMC areas topography based on GBP‐SPECT. RFA procedure significantly improved cardiac contractility indices; AMC areas completely disappeared or decreased compared with the preoperative conditions.

Conclusion

In VA patients, AMC areas were localized mostly in the right ventricle. Comparison of the results of GBP‐SPECT and EPS studies showed a relationship between AMC localizations and ectopic foci topography. The fact that AMC areas disappeared after RFA supports the hypothesis stating that the presence of AMC areas is a scintigraphic symptom of ectopic focus.
Best Practices for Besting the Bureaucracy: Avoiding Military Service in Israel
Authors: Weiss Erica
Published: September 2016

This article considers the evasion of mandatory military service in Israel. Exemption from service is granted on a number of grounds at the discretion of military bureaucrats. Each year, many young people seek to obtain such an exemption for a wide variety of reasons, both ideological and pragmatic. At their disposal is a body of knowledge, collectively assembled by young recruits who have previously encountered the bureaucracy; that is, a best practices guide to navigate the exemption process. This article examines the creation and deployment of this body of knowledge. These best practices include information about legitimate exemptions and evaluation criteria, bureaucratic procedures, a typology of bureaucrats who a young recruit will encounter, advice about the type of persona to present to the military bureaucrats, as well as the key elements of the performance of this persona. Many ethnographic accounts describe the ways the bureaucratic gaze controls, disciplines, and frustrates clients attempting to accomplish their goals. This article considers the ways clients return the gaze of the state through their own surveillance and knowledge production, and in doing so flip the script on bureaucratic control.
Multimodality, Transparency, and Food Safety in China
Authors: Tracy Megan
Published: September 2016

In September 2008, revelation of melamine‐contaminated milk supplies in China's dairy industry rocked its manufacturing sector still reeling from highly publicized food and safety scandals in 2007. Despite state and corporate interventions, regulatory and quality management issues highlighted in these earlier scandals remained. Local government and corporate actors’ attempts to suppress information about the scandal highlighted concerns about transparency, accountability, and corruption. This article is based on ethnographic research conducted in 2009 and 2010 in Beijing and Shanghai and across 2012 and 2013 in Beijing and China's Inner Mongolia Autonomous Region. My goals are twofold. First, I seek to move forward discussions of transparency in China, which often suffer from easy dismissals by academics, the media and the public alike. Second, I aim to broaden our understanding of transparency as not just fulfilling multiple functions but also as multimodal in that it is actively produced across different scales of experience and through diverse mechanisms. Using data focused on the production and monitoring of food safety, I describe the structural challenges that led to the 2008 scandal, the measures implemented in the industry to prevent future problems, and the broader discussions and interventions designed to improve China's overall food safety record.
An Injury to One Is an Injury to All? Class Actions in South African Courts and Their Social Effects on Plaintiffs
Authors: Kesselring Rita
Published: September 2016

This article contributes to one of the key issues in recent scholarship on the relation between law and society: how does engagement with the law trigger shifts in subjectivities? Scholars suggest that as groups and individuals seek recourse to the law, their subjectivities are legalized. They are skeptical of the global increase of social issues being taken to court.

I critically review these theories of ‘legalization’ by empirically tracing the implications of procedural rules onto forms of sociality among apartheid‐era victims today. With the example of a class action, an emerging legal remedy in South Africa I will show that, on the hand, procedural pressure to personalize injuries may indeed disrupt solidarity. The reason why the law is effective in producing a suspicious subject position, however, cannot be attributed to the ‘quasi‐magical power’ of the law, as Bourdieu called it, but has to be searched for in historically grown social and political circumstances apartheid victims’ find themselves in today. The law does not simply impose its logic onto the social, it can only legalize for pre‐existing societal reasons.
The Production of Indigenous Land Rights: Judicial Decisions across National, Regional, and Global Scales
Authors: Medina Laurie Kroshus
Published: September 2016

This analysis explores the circulation of legal arguments, instruments, and decisions across national, regional, and global scales to reveal the mutual interdependence of these scales and their associated bodies of law in the production of indigenous land rights. Anthropologists studying the production of international human rights law have focused primarily on the drafting and implementation of rights instruments within the UN system, but this article engages a different site for the production of rights: the judicial arena. Highlighting the role played by judicial decisions and the arguments of legal scholars in the production of indigenous land rights, this article traces the trajectory of a petition for recognition of indigenous rights to land by Mopan and Q'eqchi’ Maya of Belize, as it moved from Belize to the Inter‐American Commission on Human Rights. The resulting decision circulated through subsequent indigenous rights cases within the Inter‐American system to solidify regional jurisprudence on indigenous rights. The IACHR decision also returned to Belize, where the Supreme Court engaged it to reach its own decision on Maya land rights. In turn, the Belize Supreme Court ruling was launched into global circulation, shaping arguments concerning the content and status of international indigenous rights law.
Differential DNA methylation of the meiosis‐specific gene FKBP6 in testes of yak and cattle–yak hybrids
Authors: Li B , Luo H , Weng Q , Wang S , Pan Z , Xie Z , Wu W , Liu H , Li Q
Published: September 2016

Contents

FK506‐binding protein 6 (FKBP6) is essential for meiosis during mammalian spermatogenesis. However, the molecular regulation of FKBP6 during spermatogenesis remains unclear. In the present study, we performed molecular characterization of the meiosis‐specific gene FKBP6 in yak testes. Yak FKBP6 encodes a polypeptide of 295 amino acid residues with an FK506‐binding domain (FKBP_C) and three tetratricopeptide repeat domains. The methylation level of the FKBP6 promoter in testes was significantly higher in cattle–yak with male sterility than in yak, and the FKBP6 promoter was methylated in liver tissues in which FKBP6 is not expressed. FKBP6 promoter activity was significantly decreased after treatment with the M.SssI methyltransferase in vitro. Furthermore, the FKBP6 gene was remarkably activated in bovine mammary epithelial cells treated with the DNA methyltransferase inhibitor 5‐aza‐2‐deoxycytidine. Taken together, our results demonstrate for the first time that the FKBP6 promoter is differentially methylated in testes; together with the functional promoter analysis, this suggests that methylation of this promoter may contribute to cattle–yak male infertility.
Overcoming Barriers to Life Insurance Coverage: A Behavioral Approach
Authors: Coe Norma B. , Belbase Anek , Wu April Yanyuan
Published: September 2016

While life insurance purchase decisions have long been studied, we still do not know how people decide if they need insurance or how much they need. Using in‐depth interviews, we peer into the black box of employee decision making to learn what people know about this employee benefit, and how they decide if it is of value for them. We find that individuals understand the need for life insurance, but find many behavioral economic barriers to getting adequate coverage, including mental accounting, money illusion, and a strong role of defaults. We then conduct an online experiment of the hypothetical employee‐benefit purchase scenario, and find a few, simple interventions could help individuals better decide their life insurance needs.
Molecular mechanisms of HLA class I‐mediated immune evasion of human tumors and their role in resistance to immunotherapies
Authors: Seliger B.
Published: September 2016

Although the human immune system can recognize and eradicate tumor cells, tumors have also been shown to develop different strategies to escape immune surveillance, which has been described for the first time in different mouse models. The evasion of immune recognition was often associated with a poor prognosis and reduced survival of patients. During the last years the molecular mechanisms, which protect tumor cells from this immune attack, have been identified and appear to be more complex than initially expected. However, next to the composition of cellular, soluble and physical components of the tumor microenvironment, the tumor cells changes to limit immune responses. Of particular importance are classical and non‐classical human leukocyte antigen (HLA) class I antigens, which often showed a deregulated expression in cancers of distinct origin. Furthermore, HLA class I abnormalities were linked to defects in the interferon signaling, which have both been shown to be essential for mounting immune responses and are involved in resistances to T cell‐based immunotherapies. Therefore this review summarizes the expression, regulation, function and clinical relevance of HLA class I antigens in association with the interferon signal transduction pathway and its role in adaptive resistances to immunotherapies.
Magnetic Resonance Imaging Appearance and Mechanism of Action of Five Hemostatic Agents Used in Neurosurgery
Authors: Brundage Cord M. , Packer Rebecca A. , Jones Matthew D.
Published: September 2016

Objective

To describe the magnetic resonance (MR) image appearance of 5 hemostatic agents placed in the brain, and to review their clinical application.

Study Design

Descriptive ex vivo and in vivo study.

Animals

Canine cadavers (n=4), client‐owned dogs (n=4).

Methods

Heads from 4 canine cadavers were used, each with 5 hemostatic agents placed in specific locations in the brain. Hemostatic agents were used in their native form in 2 cadaveric brains, and in 2 others the materials were saturated with fresh whole blood prior to placement to mimic application in a field of active hemorrhage. The heads underwent MR imaging and the images were reviewed. Postoperative MRI images from 4 dogs undergoing brain tumor resection were retrospectively reviewed and compared to the images from the cadavers. All clinical cases and cadaveric specimens underwent surgical closure prior to MR imaging including placement of titanium mesh over the craniotomy defect with a dural graft of porcine small intestinal submucosa (SIS) sealed with Tisseel (fibrin sealant).

Results

The SIS and Tisseel used in the dural graft were consistently indistinguishable from the surrounding tissues on MR images. The MR imaging appearance of the remaining 4 hemostatic agents (Gelfoam, Avitene, Surgicel, and Floseal) placed on the surface or in the parenchyma of canine brain, varied with MR sequence weighting and blood saturation.

Conclusion

Accurate evaluation of the degree of brain tumor resection on postoperative MR images requires careful differentiation between hemorrhage, residual tumor, and hemostatic agents implanted.
Laparoscopic Adrenalectomy for Removal of Unilateral Noninvasive Pheochromocytomas in 10 Dogs
Authors: Pitt Kathryn A. , Mayhew Philipp D. , Steffey Michele A. , Culp William T. N. , Fuller Mark C. , Della Maggiore Ann , Nelson Richard W.
Published: September 2016

Objective

To report the surgical technique and outcome of dogs undergoing laparoscopic adrenalectomy for removal of unilateral noninvasive pheochromocytoma.

Study Design

Retrospective case series.

Animals

Dogs with unilateral noninvasive adrenal tumors (n=10).

Methods

Medical records of dogs that underwent laparoscopic adrenalectomy for histologically confirmed pheochromocytoma were reviewed. Dogs were positioned in lateral recumbency with the table tilted up to create a semi‐sternal position. Three or 4 ports were used and dissection of the mass proceeded using a combination of laparoscopic instrumentation, bipolar vessel‐sealing devices, and in some cases monopolar electrosurgical probes. Conversion rate, complications, surgical time, hospitalization time, and long‐term follow‐up were recorded.

Results

The procedure was completed without the need for conversion in 9 of 10 dogs. In 1 dog, hemorrhage obscured the visual field and conversion to an open approach was elected. In 5 cases, a 3‐port approach was used, and in 5 cases, a 4th port was placed. Median surgical time was 105 minutes (range, 65–250). Intraoperative complications included 1 splenic laceration. Postoperatively, 1 dog developed gastric dilatation‐volvulus. All dogs were discharged from the hospital. Median follow‐up time was 16.0 months (range, 6.9–38.0).

Conclusion

With careful case selection, laparoscopic adrenalectomy for resection of pheochromocytoma was feasible and could be performed efficiently by experienced laparoscopic surgeons.
Determination of Porto‐Azygos Shunt Anatomy in Dogs by Computed Tomography Angiography
Authors: Or Matan , Ishigaki Kumiko , de Rooster Hilde , Kutara Kenji , Asano Kazushi
Published: September 2016

Objective

To describe the morphology of porto‐azygos shunts in a large series of dogs using computed tomography (CT) angiography.

Study Design

Retrospective study.

Animals

Dogs (n=36) with porto‐azygos shunts.

Methods

CT angiography was performed in dogs subsequently proven to have a porto‐azygos shunt. The origin and insertion of the shunts were assessed on native images. The diameter of the porto‐azygos shunt and the portal vein, cranial and caudal to the shunt origin, were measured. The porto‐azygos shunt anatomy was studied on three‐dimensional images.

Results

All porto‐azygos shunts originated either in the left gastric vein (33 left gastro‐azygos shunts) or the right gastric vein (3 right gastro‐azygos shunts). Two left gastro‐azygos shunts had concurrent caval‐azygos continuation and 2 right gastro‐azygos shunts had a caudal splenic loop. All shunts crossed the diaphragm through the esophageal hiatus. The majority of porto‐azygos shunts (32) followed a straight pathway after traversing the diaphragm, although 4 shunts followed a tortuous route. All shunts terminated in the thoracic part of the azygos vein, perpendicular to the aorta. The shunt diameter at insertion was only 3 mm on average. The insertion site was consistently the narrowest part of the shunt.

Conclusion

CT angiography was well suited to provide anatomic details of porto‐azygos shunts and comprehensively documented that all porto‐azygos shunts had a thoracic terminus, after crossing the diaphragm through the esophageal hiatus. Different shunt types existed with minor variations.
Improved Feed-Forward Control in Track Seeking Using Iterative Learning Control
Authors: Bagherieh Omid , Horowitz Roberto
Published: September 2016

A specific class of track seeking problem has been considered in this paper, where the HDD head should follow a simple predetermined trajectory. This process is considered to be relatively slow, therefore, only VCM is used as an actuator. The accuracy of this trajectory following problem can be improved using iterative learning control, ILC. Two different ILC algorithms have been simulated and compared under existence of repeatable and non-repeatable disturbances.
Preliminary Study on Utilization of Impact Force for Snap-Fit Assembly
Authors: Wu Tsung-Liang , Mai Chin-Chia , Yeh Jih-Hsiang , Chiu Yu-tsung , Shen Ping-Hsin
Published: September 2016

The purpose of this study is to evaluate the inserting operation by impact force through the robot. Applying the most intuitive motion, like human hand, to insert the electronic onto the PCB, the robot need to move up to a desired high acceleration and only torque controlled mode is adequate for manipulating. However, the position mode presents the better accuracy for positioning than the torque control mode. Therefore, this study will conduct the assembly process by switching between position and torque controlled modes to achieve the inserting operation. The results show the feasibility of applying impact force on inserting operation and the measured acceleration is around 1.9 g that is closed to the computed input acceleration.
Thickness Uniformity Inspection With Comparison Off-Axis Digital Holography
Authors: Jin Jinan , Jeon Sungbin , Cho Janghyun , Park No-Cheol
Published: September 2016

This research proposes a comparison off-axis digital holographic technology for thickness uniformity inspection of transparent products. Compared to existing technologies, the comparison off-axis digital holographic method has advantages such as high depth resolution and large field of view. Also, the proposed method can measure the thickness differences between standard product and the ones produced by one shot imaging with tilt correction. Comparative analysis is used to demonstrate the effectiveness.
Experimental Investigation of Heat Flux at the Head-Disk Interface in Hard Disk Drives
Authors: Ma Yuan , Bogy David B.
Published: September 2016

In hard disk drives (HDDs), Thermal Fly-Height Control (TFC) is used to control the head disk spacing for reading or writing data. In order to monitor the spacing and detect possible contacts between the head and disk, a resistive temperature sensor, called Touch-Down Sensor (TDS), is embedded in the slider near potential contact points of the slider against the disk. Understanding the mechanisms of heat transfer across the head-disk interface (HDI) is of major importance, because it is closely related to the design of HDDs, including lubricant flow and contact issues, especially for Heat Assisted Magnetic Recording (HAMR) drives. In this paper, we conducted a series of experiments both on rotating and on non-rotating disks with TDS to find the cause of head temperature change and to validate the heat transfer theory based on phonon conduction. From the experiment, it is shown that air bearing cooling is not responsible for the cooling that occurs in the last nanometer before contact. Based on phonon conduction predictions, we should expect a decrease in slope of the non-contact curve as the spacing becomes less than 1 or 2 nm because of the strong increase in the heat flux due to phono conduction in this range.
Radial Transportation of Particle With a Single-Axis Transducer and the Double Reflectors
Authors: Dong Huijuan , Zhang Peng , Papouris Panagiotis
Published: September 2016

Acoustic levitation and transportation techniques has a wide applications in fields of biology, chemistry and materials science. We present an acoustic levitator consisted of one single-axis Langevin piezoelectric transducer and two reflectors. The 24.2mm-long-distance radial transportation of the Styrofoam particle is achieved by changing the resonant chamber height between the two reflectors. The optimal distance between the axis of the upper and the lower reflectors is determined as 7mm through the method of the finite element simulation. Analytical results are verified by the experimental data which also provide critical parameters to build a radial particles transportation apparatus.
Autonomous Navigation and Mapping for Mobile Robot in Unknown Environment Using Line Segments
Authors: Song Chunlin , Chen Cheng , Cui Naigang
Published: September 2016

Used widely in military and civil applications, autonomous robots have shown promising in planet exploration, seabed survey, and disaster rescue. A lot of robotic research concentrates on localization and mapping dealing with the basic problems in robotic research: “Where I am?” and “How is the environment like?”. The two problems consist a coupled problem named Simultaneous Localization and Mapping (SLAM) in unknown environment exploration. This problem is summarized by Hugh D. Whyte in his paper published in 1991 [1]. Forced by requirement of motion in unknown environment, many researchers in robotics make efforts to solve SLAM problem in recent decades.
Dynamic Friction Study on Voltage Assisted Overcoat Wearing Head-Disk Interface
Authors: Rajauria Sukumar , Canchi Sripathi , Schreck Erhard , Marchon Bruno , Dai Qing
Published: September 2016

Voltage assisted wear at the head and the disk interface is investigated with the motive of understanding the head overcoat wear processes. In this work, we report the quantitative analysis of voltage assisted wear on head carbon overcoat at high sliding speed interfaces. We found that voltage assisted TFC head wear acts asymmetrically at the interface with positive voltage leading to high wear. We quantitatively analyzed the interface using a strain gauge based friction measurement.
A Charge Pump With MPPT Circuit Employed in Batteryless Photovoltaic IoT Tags
Authors: Men Guan-Yu , Cheng Yuan-Po , Chao Paul C.-P. , Yang Ching-Cheng , Pribadi Eka Fitrah
Published: September 2016

A dc-dc regulator is proposed to attach to the battery-less solar tag applied in the Internet of Things (IoTs) market. Two main purposes in this design is to maximize the power transfer efficiency and to provide a high voltage supply to the back-end circuit. The overall circuit consists of the cross-coupled charge pump, optimal power point tracking and timing control circuit. It is expected to boost the input voltage from 0.55–0.65V to the output of 1–1.1V at 80–100μW condition. Gated PFM circuit is adopted in the optimal power point tracking system to modulate the input frequency of the charge pump to match the inner resistance of the solar cell. This system has been taped-out by TSMC 0.18UM 1P6M process twice and N-fab 0.35UM process once. The experimental results of this chip show that the voltage conversion efficiency (VCE) is 97% and the power conversion efficiency (PCE) is 11.7% at 30μW input power condition. The reason of the low efficiency has been found and improved by enhancing the pumping capacitance. The efficiency of the 3rd tape-out in N-fab has been improved to 81.2% according to the simulation results.
Dynamic Modeling and Vibration Suppression of Double Flexible Mechanical Arm System
Authors: Xu Shijie , Guan Yingzi , Fan Youhua
Published: September 2016

Mechanical arms are widely used in various industrial applications, especially in the field of aerospace and data storage [1–2]. Demands of new missions have more stringent requirements than before, and not only dimensions are larger, but also the accuracy. This raises the problem of less accuracy due to vibration of large flexible structures. A great deal of research has been recently focused on vibration suppression [3–6]. All of them have their own advantages, but they are difficult to widely used because their additional requirements on the structure and so on. For this problem, works in this article built an accurate model, and then combines it with Component Synthesis Vibration Suppression (CSVS) method [7–9]. This method can enhance vibration suppression. Results show there are almost no vibration when the maneuvering stopped.
Parametric Study of a Non-Contact Brake Actuator Using Magneto-Rheological Fluid
Authors: Li Sheng-Wei , Tsai Sung-Yu , Chang Jen-Yuan (James)
Published: September 2016

Brake has a long engineering development history and has been widely applied on mechanical components from abstain from dynamic motion. There are many different types of brake mechanism, such as using tension cable, hydraulics and electronics. According to Automotive Research and Testing Center in Taiwan [1], electronics brake is becoming a very popular and is the main stream solution for brake mechanism. In addition, electronics brake using electromagnetic field for actuating power source has been widely developed in the recent years. However, brake system with smart fluid (i.e. Magneto-Rheological or Electro-Rheological Fluid) as brake mechanism has not been a common research development topic until recent year. The world’s first commercial MR fluid brake was invented by Lord Corp. [2] which was shown in Fig. 1. In 2003, Li, W. H and Du, H. has proposed an idea of applying electromagnetic as the source of excitation for the MR fluid brake [3]. However, a significant problem has been pointed out by the research suggesting that thermal effect is the major issue in preventing the MR fluid from performing the designed task. Evidently, heat is generated when the electric current passes through the coil of the electromagnetics.
A Dynamic Model of the Magnetic Head Slider With Contact and Off-Track Motion due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces
Authors: Pathak Saurabh , Wang Shao
Published: September 2016

A computationally efficient five-degree-of-freedom dynamic model was developed to simulate the motion of a magnetic head slider under the conditions of moving-bump collision and of contact due to an expanding protrusion on the slider for thermal flying-height control, with consideration of intermolecular forces. Compared to results obtained without intermolecular forces for a bump on the rotating disk, the intermolecular forces cause a significantly greater normal contact force, a larger roll angle and a larger off-track displacement under nonzero skew. When an expanding protrusion on the slider reaches a position close to the disk surface, the intermolecular forces pull the slider into contact at an earlier time and keep the protrusion in contact for a longer duration, which, with friction under nonzero skew, results in a substantially greater off-track displacement.
Study of the Formation and Break of Lubricant Bridge in the Head Disk Interface Using Molecular Dynamic Method
Authors: Dai Xiangyu , Lei Xiao , Li Hui
Published: September 2016

Nowadays, heat assisted magnetic recording (HAMR) technology has been proposed to reach higher storage density. In this paper, the molecular dynamic (MD) simulation method is used to investigate the damage and recovery of the lubricant perfluoropolyethers (PFPE) layer under rapid heating and cooling in HAMR. Full-atom model for three-dimensional slider-lubricants-disk substrate system are built. The lubricant adheres to the diamond like carbon (DLC) substrate, and the space between slider and lubricant is filled with helium atoms. The results show that with higher heating speed, the PFPE will be easier to evaporate and form lubricant bridge. In addition, the thickness and stability of the lubricant bridge are significantly affected by the heating speed and the rotation speed of disk.