Search

The ACM SIGIR Conference on Research and Development in Information Retrieval has been experiencing significant growth over the past few years. In 2023, SIGIR received a total of 822 full paper submissions and 1,787 papers/proposals. This has brought several challenges to the conference program organization. This article reports some of the main aspects of the work conducted by the program committee (PC) co-chairs for SIGIR 2023, and discusses emergent issues of the review process and program design. We expect that this document serve as a reference for future PC co-chars and as a starting point for further discussions towards improving the review process and overall conference experience. Date: 23--27 July 2023. Website: https://sigir.org/sigir2023/. [ABSTRACT FROM AUTHOR]

This paper proposes a visualization recommender system for tabular data given visualization intents (e.g., “population trends in Italy” and “smartphone market share”). The proposed method predicts the most suitable visualization type(e.g., line, pie, or bar chart) and visualized columns(columns used for visualization) based on statistical features extracted from the tabular data as well as semantic features derived from the visualization intent. To predict the appropriate visualization type, we propose a bi-directional attention (BiDA) model that identifies important table columns using the visualization intent and important parts of the intent using the table headers. To determine the visualized columns, we employ a pre-trained neural language model to encode both visualization intents and table columns and predict which columns are the most likely to be used for visualization. Since there was no available dataset for this task, we created a new dataset consisting of over 100 K tables and their appropriate visualization. Experiments revealed that our proposed methods accurately predicted suitable visualization types and visualized columns.

This is a report on the NTCIR-16 conference held online in June 2022. NTCIR is a series of parallel and collective evaluation efforts designed to enhance research on diverse information access technologies, including, but not limited to, cross-language and multimedia information access, question-answering, text mining, and summarization. 53 active research groups from 20 countries/regions participated in one or more of the 10 different tasks in NTCIR-16. This report introduces the highlights of the conference and describes the scope and task designs of 10 tasks organized at NTCIR-16. Date: 14--17 June, 2022. Website: https://research.nii.ac.jp/ntcir/ntcir-16/. [ABSTRACT FROM AUTHOR]

Industrial networks with a database for collecting and analyzing machine information and process data are key components in production systems in Industry 4.0. In proposed IoT system, more than 300 temperature sensors were externally mounted on a carbon fiber reinforced plastics structured machine tool, and their information was collected through an OPC UA server. Based on impact tests, the spindle nose temperature was found to be correlated to the variation in compliance and resonant frequency. The carbon fiber reinforced plastics structured spindle shaft conducted heat quickly and induced a temperature increase after stopping spindle rotation. The IoT system of a temperature-analysis environment can contribute to experimental analysis and model construction for intelligent technologies.

This is a report on the NTCIR-15 conference held online in December 2020. NTCIR is a sesquiannual research project designed to evaluate various information access technologies, including information retrieval, information recommendation, question answering, natural language processing, etc. 55 active research groups from 22 countries\regions have participated in one or more of the seven tasks in NTCIR-15. This report introduces the highlights of the conference, describes the scope and task designs of the seven tasks organized at NTCIR-15. Date: 8--11 December, 2020. Website: http://research.nii.ac.jp/ntcir/ntcir-15/. [ABSTRACT FROM AUTHOR]

ABSTRACTBark stripping damages of conifer trees by Asiatic black bears (Ursus thibetanus) are confirmed in most areas inhibited by them in Japan. In this study, we conducted a field survey in Shirakawa Village, Gifu Prefecture, Japan, from 2008 to 2016 to investigate the seasonal and annual variation of bark-stripping of Japanese cedar (Cryptomeria japonica) by Asiatic black bears in relation to mast production of Fagaceae family and diet. We found that bark stripping occurred from May to July, during which sap flow in the cambium layers is high. Bark stripping frequency on Japanese cedar was negatively associated with mast production of Fagaceae hard mast. Fleshly fruit of Japanese bird cherry does not appear to affect bark stripping in contrast to other areas. Our results suggested that foods that affect frequency of bark stripping may differ among regions.

Evaluation in empirical computer science is essential to show progress and assess technologies developed. Several research domains such as information retrieval have long relied on systematic evaluation to measure progress: here, the Cranfield paradigm of creating shared test collections, defining search tasks, and collecting ground truth for these tasks has persisted up until now. In recent years, however, several new challenges have emerged that do not fit this paradigm very well: extremely large data sets, confidential data sets as found in the medical domain, and rapidly changing data sets as often encountered in industry. Crowdsourcing has also changed the way in which industry approaches problem-solving with companies now organizing challenges and handing out monetary awards to incentivize people to work on their challenges, particularly in the field of machine learning.This article is based on discussions at a workshop on Evaluation-as-a-Service (EaaS). EaaS is the paradigm of not providing data sets to participants and have them work on the data locally, but keeping the data central and allowing access via Application Programming Interfaces (API), Virtual Machines (VM), or other possibilities to ship executables. The objectives of this article are to summarize and compare the current approaches and consolidate the experiences of these approaches to outline the next steps of EaaS, particularly toward sustainable research infrastructures.The article summarizes several existing approaches to EaaS and analyzes their usage scenarios and also the advantages and disadvantages. The many factors influencing EaaS are summarized, and the environment in terms of motivations for the various stakeholders, from funding agencies to challenge organizers, researchers and participants, to industry interested in supplying real-world problems for which they require solutions.EaaS solves many problems of the current research environment, where data sets are often not accessible to many researchers. Executables of published tools are equally often not available making the reproducibility of results impossible. EaaS, however, creates reusable/citable data sets as well as available executables. Many challenges remain, but such a framework for research can also foster more collaboration between researchers, potentially increasing the speed of obtaining research results.

This is a report on the NTCIR-13 conference held in December 2017, in Tokyo, Japan. NTCIR is a series of parallel and collective evaluation efforts designed to enhance research on diverse information access technologies, including, but not limited to, cross-language and multimedia information access, question-answering, text mining and summarization, with an emphasis on East Asian languages such as Chinese, Korean, and Japanese, as well as English. 105 different research groups from 20 countries/regions participated in one or more of the nine different tasks in NTCIR-13, to compete and collaborate on a common ground and thereby advance the state of the art. This report introduces the highlights of the conference, describes the scope and task designs of nine tasks organized at NTCIR-13, and provides a brief introduction to NTCIR-14, which started from January 2018 and will be closed in June 2019, which will be the 20th anniversary since the first NTCIR Conference in the summer of 1999. [ABSTRACT FROM AUTHOR]

The third Asian Summer School in Information Access (ASSIA 2017) was held between 2nd and 5th August, 2017 in Kyoto, Japan. The summer school offered 9 lectures on information retrieval and related topics, along with a poster session and a panel discussion. This report introduces the successful international summer school in Asia attracting 63 participants from a wide range of countries. [ABSTRACT FROM AUTHOR]

This is a report on the NTCIR-12 conference held in June 2016, in Tokyo, Japan. NTCIR-12 is the twelfth sesquiannual research project for evaluating information access technologies that organizes a diverse set of tasks related to information retrieval, question answering, and natural language processing. The NTCIR-12 conference is a venue in which task organizers and task participants presented their effort on their participating tasks, and attracted 236 participants from 21 countries/regions in this round. This report introduces the highlights of the conference, describes the scope and task designs of nine tasks organized at NTCIR-12, and provides a brief introduction to NTCIR-13, which started from June 2016 and will be closed in December 2017. [ABSTRACT FROM AUTHOR]

In this paper, both nylon 6 and 2 wt% clay reinforced nylon 6 matrix nanocomposite were used for thermal exposure tests at temperatures of 80 oC and 120 oC and 150 oC, respectively. Then, the tensile tests and fatigue tests of the exposed specimens were conducted at room temperature. It was shown that the tensile strength in both nylon 6 and NCH-2 decreased with an increase in thermal exposure temperature. The brittle fracture occurred in the specimens exposed at 120 oC and 150 oC. After pre-oxidation treatment at 80 °C for 100 hours, the fatigue strength decreased 14% in nylon 6, and 8% in NCH-2. From this result, it was understood that the addition of clay in nylon 6 could suppress the decrease of fatigue strengths.

A series of copolycarbonates were prepared by transesterification polymerization of isosorbide, bisphenol A and diphenylcarbonate using several catalysts. The copolymers with the highest molecular weights were obtained using N,N-dimethylaminopyridine as a catalyst. The storage moduli of the polymers ranged from 2.3 to 3.5 GPa at 25 °C, and the tensile moduli were 1.7–2.6 GPa, increasing with the isosorbide content. The storage and tensile moduli of the polymers indicated that they could exhibit better strength than bisphenol A-based polycarbonates. These properties endow the polymers with potential for use as high-performance materials.

3kV UMOSFET with buried p-base regions was developed to realize the low on-resistance with low electric field in the gate oxide for off-state. The buried p-base region was formed simultaneously with the p-base region by utilizing MeV ion implantation. Influence by the structural parameter such as cell geometry and space between the buried p-base region and the trench gate was investigated. The hexagonal cell with high channel density exhibits an extremely low on-resistance of 6.8 mΩcm2 with threshold voltage of 5.0 V at room temperature.

Stream macroinvertebrate assemblages are expected to be affected by the abundance and constitution of litter from surrounding forests. We compared forest floor cover, overland flow, stream environment, and stream macroinvertebrate assemblages between the catchments of a Japanese cedar plantation (CP) and a primary deciduous forest (DF). Both systems experience excessive deer browsing. Understory vegetation cover was higher in the DF than in the CP in summer, although cover was low (<20 %), possibly because of excessive deer browsing. Litter cover was much higher in the CP than in the DF in summer as a result of the long abscission period, slow breakdown, and low rate of dispersal of Japanese cedar litter compared to deciduous litter. Monthly overland flow was always lower in the CP than in the DF, and substrate size was smaller in the DF stream. In the CP, cedar litter accumulated in the stream, probably because of its low breakdown rate and morphology, and abundant shredder taxa characterized the macroinvertebrate assemblage. In contrast, abundant burrower taxa characterized the macroinvertebrate assemblage in the DF stream. These results imply that Japanese cedar litter functions in structuring the macroinvertebrate assemblage by supplying persistent food resources for detritivores, and by buffering fine sedimentation via overland flow under excessive deer browsing.Stream macroinvertebrate assemblages are expected to be affected by the abundance and constitution of litter from surrounding forests. We compared forest floor cover, overland flow, stream environment, and stream macroinvertebrate assemblages between the catchments of a Japanese cedar plantation (CP) and a primary deciduous forest (DF). Both systems experience excessive deer browsing. Understory vegetation cover was higher in the DF than in the CP in summer, although cover was low (<20 %), possibly because of excessive deer browsing. Litter cover was much higher in the CP than in the DF in summer as a result of the long abscission period, slow breakdown, and low rate of dispersal of Japanese cedar litter compared to deciduous litter. Monthly overland flow was always lower in the CP than in the DF, and substrate size was smaller in the DF stream. In the CP, cedar litter accumulated in the stream, probably because of its low breakdown rate and morphology, and abundant shredder taxa characterized the macroinvertebrate assemblage. In contrast, abundant burrower taxa characterized the macroinvertebrate assemblage in the DF stream. These results imply that Japanese cedar litter functions in structuring the macroinvertebrate assemblage by supplying persistent food resources for detritivores, and by buffering fine sedimentation via overland flow under excessive deer browsing.

Xenos is a strepsipteran genus whose members are parasitic to eusocial wasps, including the hornet genus Vespa. We undertook an extensive sampling of strepsipterans in Xenos from hornets collected in East Asia and performed molecular phylogenetic analyses based on mitochondrial cytochrome c oxidase subunit I gene sequences (652 bp) to investigate the cryptic diversity among 21 individuals of strepsipterans. The analyses, accompanied by morphological examination, revealed that these strepsipterans represent two distinct species, X. moutoni du Buysson, 1903 and X. oxyodontes sp. nov. The two species differed in their host-utilization pattern: the latter was almost specific to Vespa analis and V. simillima, whereas the former was associated with other species in Vespa. [ABSTRACT FROM AUTHOR]

Nylon 6 clay hybrid (NCH) composite consists of nano-sized Montmorillonite and nylon 6 matrix. The testing materials were nylon 6, NCH-2 (2 wt% clay reinforced composite) and NCH-5 (5 wt% clay reinforced composite). Fatigue tests at the glass transition temperatures (35 ºC and 50 ºC) were performed with a stress ratio of 0.1 and frequency of 0.1Hz. NCH-2 had the highest fatigue strength at room temperature, but NCH-5 had the highest fatigue strengths at 35 ºC and 50 ºC. It was found that the fracture origin changed from surfaces to interior of specimens with an increase in temperature in NCH-2 and NCH-5.

We assessed the host-use pattern of the sponge-endosymbiotic bivalve Vulsella vulsella and its demographic consequences in an inland sea in Okinawa Island, Japan. Vulsella vulsella utilized only one massive globular sponge species Spongia sp. as a host, and no Spongia sp. without V. vulsella were found. Individual sponges contained 9-248 live bivalves and 0-222 dead bivalves. The densities of live and dead bivalves in individual sponges were approximately constant irrespective of sponge size, indicating that available space is very scarce inside each sponge. The size distribution of bivalves was skewed to small, young individuals less than 30 mm in shell height, although the estimated largest possible size was 106 mm. The bivalve population at each sampling date was composed of three yearly cohorts, and recruitment of juveniles occurred in the summer. The bivalves became sexually mature as males within one year after recruitment and changed sex from male to female as they grew. The size and sex distributions of the bivalve were largely similar among sponges regardless of sponge size, suggesting that the recruitment, growth, longevity, and sex change of the bivalve were strictly regulated, probably by the high water temperature and strong waves generated by typhoons in summer months. [ABSTRACT FROM AUTHOR]

We present the prototype of a new, collinear-type energy-filtered X-ray photoemission electron microscope (EXPEEM) using a multi-pole, aberration-corrected air-core coil Wien filter (WF) analyzer. We have designed the new WF with 12-pole electrodes and magnetic poles to reduce spherical aberrations and fringe effects. We assess the performance of the WF using an electron energy analyzer for PEEM. The sensitivity is enhanced 10--100 fold compared with a simple, two electrodes plus two magnetic poles type WF. Cu 2p3/2and Au 4f7/2photoelectron energy selected images are obtained in a laboratory-scale source within several minutes. The energy and spatial resolutions of our prototype EXPEEM are estimated to be 3 eV and 7 μm, respectively.

A nylon 6-clay hybrid (nanocomposite, NCH) was developed by Toyota CRDL group. In the NCH, the silicate layers of clay mineral are dispersed on a nanometer level and are strongly interacted with the matrix, and then significant improvements in the mechanical properties of the material or the discovery of unexpected new properties were realized. Polypropylene (PP) is the most widely used polymer, and then an appearance of a PP–clay nanocomposite has been desired for a long time. As a PP does not include any polar groups in its backbone, it was thought that the homogeneous dispersion of the silicate layers would not be realized. But we have developed successfully PP–clay nanocomposite using organoclay and modified PP. That is, organophilic clay, PP oligomer carrying polar groups and PP were melt-blended. This is a direct polymer intercalation process for preparing polymer nanocomposites by melt compounding, a useful process from an industrial standpoint. We have also developed successfully other polyolefin polymers (polyethylene), polyolefin rubbers (ethylene–propylene elastomer, ethylene–propylene diene monomer) and nanocomposites by this direct polymer intercalation process or by techniques based on direct polymer intercalation process. These prepared polyolefin nanocomposites exhibit superior mechanical, thermal and gas barrier properties.

The burrows created by benthos in tidal flats provide various habitats to other organisms. Echiuran burrows are unique among these in being persistently disturbed by the host's undulating activity, but little is known on how symbionts adapt to such a unique habitat. We report here the morphological and ecological adaptation by two bivalve species of Basterotia (Sportellidae), including one new species, which are commensals with burrowing echiuran worms. The burrows of Ikedosoma gogoshimense were inhabited by Basterotia gouldi at intertidal gravelly mud flats in the central Seto Inland Sea, whereas those of Ochetostoma erythrogrammon were inhabited by Basterotia carinata n. sp. at an intertidal gravelly coral-sand flat at Amami-Ohshima Island. Both bivalve species were found embedded in the burrow wall with their posterior inhalant and exhalant apertures gaping to the burrow lumen, suggesting that they utilize the water currents created by host echiurans. The posteriorly robust, laterally inflated shell with developed carina is considered an adaptation to symbiotic life, as it is exposed to pressure caused by the host's persistent undulating activity. Females of Basterotia bivalves were larger than males, suggesting size-dependent sex change, and possessed brooded veligers in the ctenidium. Our findings suggest that species-specific intimate association with echiurans may be widespread among the Sportellidae bivalves, whose biology remains poorly understood. [ABSTRACT FROM AUTHOR]

High‐molecular‐weight polythiocaprolactone (PTCL) was prepared in a green process via lipase‐catalyzed ROP of a cyclic 6‐mercaptohexanoic acid (6MH) oligomer. PTCL was readily depolymerized by lipase to cyclic 6MH in dilute toluene solution, which was then readily repolymerized by the same lipase to produce PTCL with the same $\overline {M} _{{\rm w}} $as the initial PTCL in a chemical recycling process. The Tmof PTCL was higher than that of the corresponding PCL. A P(TCL‐co‐CL) copolymer with 60 mol‐% TCL (6MH) units showed a higher Tmas the PCL homopolymer. Similar apparent Kmvalues were obtained for the cyclic 6MH oligomers and caprolactone oligomers, however, the Vmaxof cyclic 6MH oligomers was significantly lower than that of the corresponding caprolactone oligomers.

Due to its tectonically uplifted, mountainous landscape and copious rainfall, the Japanese archipelago possesses plentiful, persistent groundwater in alluvial plains. However, Phreatodytes, an endemic water beetle genus found in groundwater, is now critically endangered due to the devastation of subterranean water ecosystems. Phreatodytes beetles were collected from driven wells near the Ooi River estuary in central Japan. The beetles were distinguished from all described species by their thoracic and genital morphologies, and described as a new species, Phreatodytes haibaraensis. The unique habitat of this species is the hyporheic zone of a gravelly riverbed in an estuary, and the habitat represents the eastern limit of the known distribution range of the genus. Molecular phylogenetic analysis based on mitochondrial and nuclear gene sequences revealed that Phreatodytes is a member of the Noteridae and forms a dade with Notomicrus. This suggests that the genus colonized the hyporheic zone from surface waters, and that it adapted to subterranean interstitial life by becoming minute and slender, by losing its eyes, pigmentation, as well as its ability to fly and swim, and by developing a permanent underwater life cycle, and erect hairlike setae on the thorax and elytra. In addition to the beetle, several stygobiontic species, including mollusks and fishes, were found in pumped groundwater. These results suggest that the gravelly riverbed of a rapid river estuary in Central Japan harbors biodiverse, locally differentiated hyporheic organisms comprising a unique subterranean interstitial ecosystem. [ABSTRACT FROM AUTHOR]

UMOSFET is theoretically suitable to decrease the on-resistance of the MOSFET. In this study, in order to determine the cell structure of the SiC UMOSFET with extremely low on-resistance, influences of the orientation of the trench and the off-angle of the wafer on the MOS properties are investigated. The channel resistance, gate I-V curves and instability of threshold voltage are superior on the {11-20} planes as compared with other planes. On the vicinal off wafer, influence of the off-angle disappears and the properties on the equivalent planes are almost the same. The obtained results indicate that the extremely low on-resistance with the high stability and high reliability is possible in the SiC UMOSFET by the hexagonal cell composed of the six {11-20} planes on the vicinal off wafer, and actually an extremely low channel resistance was demonstrated on the hexagonal UMOSFET with the six {11-20} planes on the vicinal off wafer.

Reliability of the gate oxide is influenced by the device structure and the processes. In the SiC MOSFET, the surface morphology is degraded by the high temperature activation RTA, and the degradation is remarkable on the n+ source region. This study develops the method to suppress the degradation of the reliability of the gate oxide on the carbon face. By utilizing the carbon cap for the RTA and the high density O2 plasma etching to remove the carbon cap, the reliability is drastically improved both on the un-implanted and the implanted surfaces. Especially, the degradation of the reliability is perfectly suppressed on the un-implanted surface.

Accurate measurement of large step heights using multiple-wavelength holographic interferometry is realized using laser diodes. Due to the high-resolution wavelength tunability of such lasers, a pair of holograms with a wavelength difference of less than 0.01 nm is recorded and used to extract a phase difference having a large synthetic wavelength. Phase differences with synthetic wavelengths ranging from 2.5 to 73 mm are extracted by using pairs of holograms with wavelength differences between 0.3 and 0.01 nm. By combining the phase differences, measurements with a step height of 18 mm and an rms error of 0.04 mm could be achieved. The requirements for performing the phase unwrapping are discussed. Precise knowledge of the recording wavelengths is required to correctly perform this unwrapping.

The C(000-1) face of 4H-SiC has a lot of advantages for the power device fabrication such as the highest oxidation ratio and a smooth surface. However, the DMOS type power MOSFETs on the C(000-1) face have not been realized because of the difficulty of epitaxial growth and of high quality MOS interface formation. We have systematically investigated the device fabrication techniques for power MOSFETs on the C(000-1) face, and succeeded with the IEMOS which have blocking voltage of 660V and an on-resistance of 1.8mΩcm2 and excellent dynamic characteristics.

4H-SiC MOSFET on carbon face exhibits the high channel mobility when the gate oxide is formed by pyrogenic wet oxidation. However, this improvement is not proof against the metallization annealing which is indispensable in the fabrication of the SiC power MOSFETs. We develop the alternative metallization process suitable for the high channel mobility on the carbon face. The metallization annealing in hydrogen ambient has much effect to suppress the degradation of the channel mobility. The lateral MOSFET with the ohmic contact formed by hydrogen annealing exhibits the high channel mobility which is comparable to the channel mobility of the lateral MOSFET formed without metallization annealing.

The Ogasawara (Bonin) Islands are oceanic islands of volcanic origin located in the northwestern Pacific Ocean about 1,000 km south of the Japanese mainland. A large carpenter bee, Xylocopa (Koptortosoma) ogasawarensis, is endemic to the islands but its closest relative is unknown. The Ogasawara Islands are geographically closest to the Japanese Archipelago, but this area is inhabited only by species of a different subgenus, Alloxylocopa. Thus, X. ogasawarensis is commonly thought to have originated from other members of Koptortosoma, which is widely distributed in the Oriental tropical region. In this study, we investigated the origin of X. ogasawarensis using a phylogenetic analysis of Xylocopa based on four genes: mitochondrial cytochrome oxidase subunit I (COl) and cytochrome b (Cyt b), and nuclear elongation factor-1α (EF-1α) and phosphoenolpyruvate carboxykinase (PEPCK). A combined analysis of the four genes strongly suggests that Koptortosoma is a large, polyphyletic group, within which Alloxylocopa is embedded. Xylocopa ogasawarensis emerged as the species most closely related to Alloxylocopa and not to Oriental species of Koptortosoma. Contrary to previous views of the origin of X. ogasawarensis, our results suggest that X. ogasawarensis and Alloxylocopa share a common origin and diverged after they colonized the island regions of East Asia. [ABSTRACT FROM AUTHOR]

Here we present multiple-wavelength digital holographic interferometry with a wide measurement range using laser diodes. Small wavelength differences can be easily realized by the wavelength tuning of laser diodes with injection current controls. A contour map of an object with a wide measurement range and a high sensitivity is demonstrated by combining a few contour maps with several measurement sensitivities. Synthetic wavelengths are calibrated using a known height difference. This alleviates the need to have high precise knowledge of the recording wavelengths. The synthetic wavelengths ranged from ~3 mm for high measurement sensitivity to ~4 cm for wide measurement range. An rms error of ~35 μm for a ~1 cm height measurement is shown. The measured profile of holographic interferometry agrees with a standard stylus instrument.

Two novel types of chemically recyclable ester‐containing polyurethanes, namely, a diol‐diacid‐type poly(diester‐urethane) (PDEU) and a hydroxy acid type poly(ester‐urethane) (PEU), were prepared by a green synthetic route that avoids the use of hazardous diisocyanate. The urethane linkage was introduced by the reaction of ethylene carbonate with amino alcohols and amino acids to form urethanediol and urethane‐containing hydroxy acids, respectively. The urethanediol underwent polymerization with dimethyl adipate in the presence of lipase to produce a high‐molecular‐weight PDEU, while PEU was prepared by the lipase‐catalyzed direct polycondensation of the urethane‐containing hydroxy acid monomer. The periodic introduction of ester linkages into the polyurethane chain afforded primary biodegradation points and chemically recyclable segments. Both PDEU and PEU were readily degraded in the presence of lipase into oligomers which were readily repolymerized in the presence of the same enzyme.

In cultivation mutualisms, farming animals prepare fields for cultivars, enhance their growth and harvest them. For example, in terrestrial ecosystems, plant–herbivore cultivation mutualisms arose between humans and their crops only relatively recently. We discovered an obligate cultivation mutualism between a damselfish and an alga in a coral reef ecosystem. The damselfish, Stegastes nigricans, manages algal farms through territorial defence against the invading grazers and through weeding of unpalatable algae. As a result, the algal farms of S. nigricansare dominated by one species, Polysiphoniasp. We performed an exhaustive survey of algal assemblages inside and outside the territories of five damselfish species around the Ryukyu Islands, Japan, using molecular and morphological characteristics. Polysiphoniasp. 1 grew exclusively inside the farms of S. nigricans, and never elsewhere. Since only Polysiphoniasp. 1 is harvested and consumed by the damselfish as a staple food, this interdependent relationship is an obligate cultivation mutualism. This is the first record of an obligate plant–herbivore cultivation mutualism in a marine ecosystem. Our data also suggest that three other Polysiphoniaspecies are facultatively mutual with, commensal with, or parasitic on other damselfish species.

The channel mobility in the SiC MOSFET degrades on the rough surface of the p-well formed by ion implantation. Recently, we have developed a double-epitaxial MOSFET (DEMOSFET), in which the p-well comprises two stacked epitaxially grown p-type layers and an n-type region between the p-wells is formed by ion implantation. This device exhibited a low on-resistance of 8.5 m[removed info]cm2 with a blocking voltage of 600 V. In this study, to further improve the performance, we newly developed a device structure named implantation and epitaxial MOSFET (IEMOSFET). In this device, the p-well is formed by selective high-concentration p+ implantation followed by low-concentration p- epitaxial growth. The fabricated IEMOSFET with a buried channel exhibited superior characteristics to the DEMOSFET. The extremely low specific on-resistance of 4.3 m[removed info]cm2 was achieved with a blocking voltage of 1100 V. This value is the lowest in the normally-off SiC MOSFETs.

SiC power MOSFETs are expected to be normally-off type fast switching devices. The on-resistance of SiC power MOSFETs is much higher than the value predicted from the physical properties of SiC. This is caused by the low channel mobility due to high interface state density (Dit). We have already reported that 4H-SiC MOSFETs on the C(0001 _ ) face had higher inversion-channel mobility. However, there is the SiO2/SiC interface roughness problem in SiC MOSFETs. There are many steps at the SiO2/SiC interface because a high off-angle is necessary for SiC epitaxial growth. These steps might make SiO2/SiC interfaces rough, which leads to reduction of channel mobility. In this work, we have investigated the effect of the SiO2/SiC interface roughness caused by the off-angle on the inversion channel mobility of 4H-SiC MOSFETs fabricated on the C(0001 _ ) face. The inversion-channel mobility of MOSFETs fabricated on the 4H-SiC C(0001 _ ) face substrate with the vicinal off-angle(0.8°) is higher than that of MOSFETs fabricated on the 4H-SiC C(0001 _ ) face substrate with the 8° off-angle. Reduction of the off-angle is very useful for improvement of channel mobility. A C(0001 _ ) epitaxial substrate with the vicinal off-angle would be suitable for SiC DMOSFETs.

Summary:Aliphatic dithiol‐diacid type polythioesters were first enzymatically prepared by the direct polycondensation of hexane‐1,6‐dithiol and diacid diesters using the immobilized lipase from Candida antarctica(lipase CA). As a typical example, diethyl sebacate and hexane‐1,6‐dithiol were polymerized using lipase CA in bulk in the presence of molecular sieves 4A to produce the corresponding polythioester with an $\overline M _{\rm w}$of 10 200 in 90% yield. Both the melting and crystallization temperatures of the produced polythioesters were higher when compared to those of the corresponding polyoxyesters. A higher molecular weight polythioester was produced using lipase in a two‐step procedure, i.e., cyclization with subsequent ring‐opening polymerization.

Resole‐type phenol resin–clay nanocomposites have been prepared successfully by melt compounding phenol resin with organophilic clay. In the resulting phenol resin–clay nanocomposite, the silicate layers of the clay were exfoliated and dispersed as monolayers. The nanocomposite exhibited higher long‐term heat resistance when compared with unmodified phenol resin. It was surmised that the silicate layers of the clay acted as barriers to oxygen penetration into the resin, as the degree of heat degradation of the nanocomposite was much lower than that of the straight phenol resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3236–3240, 2006

Isobutylene isoprene rubber (IIR)‐clay nanocomposites have been prepared successfully by melt intercalation with maleic anhydride‐grafted IIR (Ma‐g‐IIR) and organophilic clay. In IIR‐clay nanocomposites, the silicate layers of the clay were exfoliated and dispersed into the monolayer. The nanocomposites exhibited greater gas barrier properties compared with those of Ma‐g‐IIR. When 15 phr clay was added, gas barrier properties were 2.5 times greater than those of Ma‐g‐IIR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1182–1188, 2006

Nylon 6-clay hybrid (NCH) was characterized by temperature-programmed pyrolysis (TPPy) techniques such as TPPy-mass spectrometry and TPPy-gas chromatography mainly focusing on the interaction between nylon 6 molecule and the surface of silicate monolayers in the NCH samples, which leads to the superior properties of the hybrid nanomateirals. Pyrolysis profile of nylon 6 matrix in the NCH samples was gradually shifted to lower temperature region with increase in the clay content. The yields of main pyrolysis products such as e-caprolactam from the NCH samples decreased with increase in the clay content, whereas those of the nitrile compounds significantly increased. These results suggested that the clay surface accelerate cis-elimination reaction of nylon 6 matrix in the NCH samples to form the nitrile compounds rather than intramolecular amide exchange to e-caprolactam. Based on the changes in pyrolysis behaviors of nylon 6 matrix in the NCH samples, the interaction between positively charged NH proton of nylon 6 molecules and negatively charged clay surface was proposed which would stabilize the six-membered transition state during pyrolysis.

Calcium carbonates and gypsum are often used to improve the chemical status of acid soils. This study discusses the effects of gypsum and polyacrylamide (PAM) application on infiltration and erodibility of a Japanese acid soil. Acid Kunigami mahji soil (sedimentary rock derived, Typic Hapludult) from Okinawa was packed into an acrylic plastic box, and simulated rainfall of 40 mm h-1 was applied. Prior to the rainfall, 2.5 t ha-1 of gypsum and/or 15 kg ha-1 of non-ionic or anionic PAM were applied onto soil surface. During a rainfall, surface runoff was collected periodically, and sediment concentration, pH, and electric conductivity of the runoff were measured. Gypsum application enhanced surface runoff. During the rainfall, EC of the runoff was greater than the critical coagulation concentration of the clays of the mahji soil, however the soil became dispersive with gypsum application. PAM application could improve infiltration of gypsum amended mahji soil and reduce sediment loss.

This paper reports on the degradation of inversion channel mobility of SiC MOSFET caused by the increase of channel doping. SiC MOSFETs were fabricated on three wafers, the doping concentrations of the epitaxial layer of which were 16 10 2× cm-3 (sample A), 17 10 2× cm-3 (sample B) and 17 10 4× cm-3 (sample C). The field effect mobility sharply decreases as the doping concentration increases. Hall mobility measurements have been done to investigate the degradation of the mobility due to doping. The measurement of sample A shows that, as a consequence of the decrease of the free carrier density due to MOS interface traps, the Hall mobility is as much as a factor of ten higher than the field effect mobility. In contrast, in regard to the measurement of sample B and sample C, we encountered unstable Hall voltage and could not obtain reproducible results. This implies that such high-density traps are generated that a channel disappears in the higher-doping samples.

We have fabricated lateral RESURF MOSFETs on 4H-SiC(0001) Si-face and (000-1) C-face substrates, and compared those properties. The channel mobility of a lateral test MOSFET on a C-face was 41 cm2/Vs, which was much higher than 5 cm2/Vs for that on a Si-face. The specific on-resistance of the lateral RESURF MOSFET on a C-face was improved to 79 mΩcm2 as comparison with 2400 mΩcm2 for Si-face. The breakdown voltage was 490V for Si-face and 460V for C-face, which was 82% and 79% of the designed breakdown voltage of 600V, respectively. The device breakdown occurred destructively at the gate electrode edge.

Not Available

Neurons in the monkey inferior temporal cortex (IT) have been shown to respond to shapes defined by luminance, texture, or motion. In the present study, we determined whether IT neurons respond to shapes defined solely by binocular disparity, and if so, whether signals of disparity and other visual cues to define shape converge on single IT neurons. We recorded extracellular activity from IT neurons while monkeys performed a fixation task. Among the neurons that responded to at least one of eight random-dot stereograms (RDSs) containing different disparity-defined shapes, 21% varied their responses to different RDSs. Responses of most of the neurons were positively correlated between two sets of RDSs, which consisted of different dot patterns but defined the same set of eight shapes, whereas responses to RDSs and their monocular images were not correlated. This indicates that the response modulation for the eight RDSs reflects selectivity for shapes (or their component contours) defined by disparity, although responses were also affected by dot patterns per se. Among the neurons that showed selectivity for shapes defined by luminance or disparity, 44% were activated by both cues. Responses of these neurons to luminance-defined shapes and those to disparity-defined shapes were often positively correlated to each other. Furthermore the stimulus rank, which was determined by the magnitude of responses to shapes, generally matched between these cues. The same held true between disparity and texture cues. The results suggest that the signals of disparity, luminance, and texture cues to define the shapes converge on a population of single IT neurons to produce the selectivity for shapes.

Polypropylene–clay hybrids (PPCHs) were prepared by melt blending maleic anhydride modified PP and organophilic clay. In these PPCHs the silicate layers of the clay were exfoliated and dispersed to the monolayers. The hybridization of the clay in PP was achieved with modified PP with a small amount of maleic anhydride groups. The tensile modulus of the PPCH with 5 wt % clay was 1.9 times higher than that of the matrix resin at 25°C. The dynamic storage moduli (E') of the PPCHs were also higher than those of the modified PP. The E' was 2.5 times higher than that of the matrix resin at 60°C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1918–1922, 2000

OBJECTIVES

The inferior temporal cortex (IT) of the monkey, a final stage in the ventral visual pathway, has been known to process information on two-dimensional (2-D) shape, color, and texture. On the other hand, the dorsal visual pathway leading to the posterior parietal cortex has been known to process information on location in space. Likewise, neurons selective for binocular disparity, which convey information on depth, have been found mainly in areas along the dorsal visual pathway. Here, we report that many neurons in the IT are also selective for binocular disparity. We recorded extracellular activity from IT neurons and found that more than half of the neurons changed their response depending on the disparity added. The change was not attributed to monocular responses or eye movements. Most neurons selective for disparity were “near” or “far” cells; they preferred either crossed or uncrossed disparity, and only a small population was tuned to zero disparity. Disparity-selective neurons were also selective for shape. Most preferred the same type of disparity irrespective of the shape presented. Disparity preference was also invariant for the fronto-parallel translation of the stimuli in most of the neurons. Finally, nearby neurons exhibited similar disparity selectivity, suggesting the existence of a functional module for processing of binocular disparity in the IT. From the above and our recent findings, we suggest that the IT integrates shape and binocular disparity information, and plays an important role in the reconstruction of three-dimensional (3-D) surfaces.

In area TE of the macaque inferior temporal cortex, horizontal axons running parallel to the pial surface mediate interactions between laterally displaced sites across the cortex. We examined the spatial distribution and the types of cells that give rise to these horizontal axons, which are important factors in determining the nature of the lateral interactions in TE.

• Acellular pertussis vaccines, which have been used in Japan since 1981, vary in antigenic constituents among manufacturers. First, to assess the immunogenicity by manufacturer and patient age, 161 children aged 3 months to 2 years were immunized by acellular pertussis vaccine from one of three Japanese manufacturers, Biken, Takeda, or Kitasato. Anti-pertussis toxin antibody responses for children immunized with Takeda and Kitasato vaccines were comparable with patients with pertussis in the convalescent stage, and anti-pertussis toxin antibody response for Biken vaccine was far higher than those of convalescing patients. Anti-filamentous hemagglutinin antibody responses for the children given the three vaccines were far higher than those of the patients. Weak serotype 1.3 agglutinin responses were observed only in children administered the Takeda vaccine. Comparing these antibody responses among various age groups, the immunogenicity of acellular vaccines in children aged 3 to 6 months was comparable with children aged 2 years. Second, to assess the manufacturer-specific efficacy, 495 households of patients with pertussis were surveyed from 1981 to 1988. The estimated efficacy of the acellular pertussis vaccines in children aged 2 to 8 years was 82%, and there were no major differences in the secondary attack rates among children immunized with acellular pertussis vaccine from each manufacturer, ie, 12.5% (1/8) for Biken, 11.1% (2/18) for Takeda, and 5.9% (1/17) for Kitasato. We conclude from these two studies that similar efficacy was observed in children aged 2 years or older for acellular pertussis vaccines from the three manufacturers, which produced anti-pertussis toxin antibody responses comparable with patients with pertussis and far higher antifilamentous hemagglutinin antibody responses than in the convalescing patients, and that age did not affect the immunogenicity of acellular vaccines.(AJDC. 1989;143:655-659)

High quality holograms of flat objects are produced by developing an achromatic-fringe system that consists of a monochromatic but spatially incoherent source, a holographic beam splitting device, and a pair of Fourier transform lenses. The effects of using an incoherent extended source and the transfer characteristics of the holograms are discussed. Emphasis is also placed on the advantages of developing lens Fourier transform holography along with the practical lens systems. A further possible extension of the system to attain high storage density as well as high quality holograms is proposed by making use of a new type of pseudorandom phase sequence.

The population dynamics and the relative importance of bottom-up and top-down effects in a plant-leafminer-multiparasitoid interaction was studied between 1981 and 1990 in a natural forest in Kyoto, Japan. The leafminer, Chromatomyia suikazurae (Agromyzidae, Diptera), passed two generations (G1 and G2) on Lonicera gracilipes (Caprifoliaceae). The G1 population in February was free from parasitoid attack, and the mortality in G1 was mainly caused by resource limitation. Intraspecific competition for resources occurred at the larval stage in G1, and the larval mortality was density-dependent. The G1 adult density was resource-limited (the number of newly opened leaves), and its variability was lower than that of G2. The G2 population in April was not resource-limited but subject to intense attack by a species-rich parasitoid complex, and thus total mortality was much larger than that in G1. Significant density dependence was detected not in larval but in pupal mortalities, which were mainly caused by parasitism by parasitoids that attacked the pupa. The host population alternately experienced “bottom-up” effects during the larval stage in G1 and “top-down” effects during the pupal stage in G2. Overall population fluctuation was non-cyclic and mainly due to climatically-induced fluctuation of available plant resources in G1.