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This article represents a systematic effort to answer the question, What are archaeology’s most important scientific challenges? Starting with a crowd-sourced query directed broadly to the professional community of archaeologists, the authors augmented, prioritized, and refined the responses during a two-day workshop focused specifically on this question. The resulting 25 “grand challenges” focus on dynamic cultural processes and the operation of coupled human and natural systems. We organize these challenges into five topics: (1) emergence, communities, and complexity; (2) resilience, persistence, transformation, and collapse; (3) movement, mobility, and migration; (4) cognition, behavior, and identity; and (5) human-environment interactions. A discussion and a brief list of references accompany each question. An important goal in identifying these challenges is to inform decisions on infrastructure investments for archaeology. Our premise is that the highest priority investments should enable us to address the most important questions. Addressing many of these challenges will require both sophisticated modeling and large-scale synthetic research that are only now becoming possible. Although new archaeological fieldwork will be essential, the greatest pay off will derive from investments that provide sophisticated research access to the explosion in systematically collected archaeological data that has occurred over the last several decades.
It has been established that material surface topography can have a significant effect on biological cell adhesion, in the absence of changes in surface chemistry. Such investigations were typically performed using surface features with size on the order of microns, comparable to the dimensions of the cells. It has been demonstrated that sub-micron sized topographies that cannot be created via contact lithography also influence cell behavior. The ability to affect cell adhesion is a prime consideration in the development of novel biomaterials. This study reports a two-stage replication molding process for fabricating ordered sub-micron sized features over a large area of biomedical polyether(urethane urea). Such a technique has great applicability in the area of long-term implantable materials as a method for influencing cell-material interactions.
Nanoporous carbon materials with high surface area (1500 – 2000 m2/g) and narrow pore size distribution ranging from 1 – 3 nm were synthesized using polyfurfuryl alcohol/polyethylene glycol diacid and coal tar pitch/polymer blends. Electrical double layer capacitance of synthesized carbon was measured using cyclic voltammetry. There is a strong correlation between the surface area of the carbon and the specific capacitance. Carbon that had surface area smaller than 1000 m2/g had specific capacitance less than 50 F/g while the carbons having surface area from 1000 – 1500 m2/g showed specific capacitances in the order of 200 -250 F/g. It was shown that the mesoporosity and macroporosity in the parent carbon are critical for both activation and as well as the specific capacitance of the material. The use of these carbons in EDLCs was also demonstrated by fabricating a two-electrode ultracapacitor.
Highly transparent films with tailorable sheet resistivity were prepared by ion-beam sputtering of indium tin oxide (ITO) with MgF2 or SiO2 in the presence of high-purity air. Sheet resistivities of 103−101 ohms/square (ω/–) and visible transmittances as high as 92% (not corrected for substrate absorption) were obtained in films ∼30 nm thick. Resistivity increased by as much as two orders of magnitude in the first year after preparation; however, thicker films (e.g. 80 nm) were much more stable but somewhat less transparent. Preliminary data from exposure of film samples to atomic oxygen in a plasma asher indicate minimal degradation in optical properties. Heat-treating pure ITO in air produced transparent, slightly conductive films but with poorer stability of sheet resistivity in air than co-deposited ITO with either SiO2, or MgF2. Electrical transport measurements yielded new information on the electronic properties of ITO and related materials. These films show promise as low-absorption static bleedoff coatings for space photovoltaic arrays as well as CRT faceplates and other commercial applications.
Among different MEMS wafer level bonding processes glass frit bonding provides reliable vacuum tight seals in volume production. The quality of the seal is a function of both seal glass materials and the processing parameters used in glass frit bonding. Therefore, in this study Taguchi L18 screening Design of Experiment (DOE) was used to study the effect of materials and process variables on the quality of the glass seal in 6” silicon wafers bonded in EVG520IS bonder. Six bonding process variables at three levels and two types of sealing glass pastes were considered. The seals were characterized by Scanning Acoustic Microscopy (SAM), cross sectional Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX). The results were quantified into four responses for DOE analysis. Key results are a) peak temperature has the strongest influence on seal properties, b) hot melt paste has significantly lower defects compared to liquid paste, and c) peak firing temperatures can be as low as 400°C under certain conditions.
The probability that a fast charged particle slowing down in a plasma will react with an ambient ion prior to thermalization is calculated, as is the probability that an ambient ion scattered by the incident particle will similarly react. Results are given for an α particle from the DT reaction in a DT plasma.
Fifty-seven children with cerebral palsy (CP) and imaging evidence of vascular thrombosis (study group) and 167 children with CP and other imaging finds (control group)were selected. Sixty-one per cent of the study group were male and 53 (93%) had spastic hemiplegia compared with the control group, of whom 55% were male and 54 (32%) had a diagnosis of spastic hemiplegia. Mean age was 5 years 11 months (SD 5y 1mo) for the study group and 7 years 7 months (SD 4y 7mo) for the control group. Blood spots on Guthrie cards or buccal swabs were used to test both groups and their mothers for the factor V Leiden (fVL) mutation, which predisposes carriers to thrombophilia. Mothers were interviewed to gather antenatal, perinatal, demographic, and socio-economic data. The frequency of the fVL mutation in children with evidence of vascular thrombosis and their mothers was not statistically different from the frequency in children with CP with other imaging findings and their mothers. The frequency of the fVL mutation was significantly higher than the expected population frequency of 4% in the study group (10.5%, p=0.012) and in mothers of the control group (7.2%, p=0.036).
To examine a comprehensive approach for preventing percutaneous injuries associated with phlebotomy procedures.
Design and Setting:
From 1993 through 1995, personnel at 10 university-affiliated hospitals enhanced surveillance and assessed underreporting of percutaneous injuries; selected, implemented, and evaluated the efficacy of phlebotomy devices with safety features (ie, engineered sharps injury prevention devices [ESIPDs]); and assessed healthcare worker satisfaction with ESIPDs. Investigators also evaluated the preventability of a subset of percutaneous injuries and conducted an audit of sharps disposal containers to quantify activation rates for devices with safety features.
The three selected phlebotomy devices with safety features reduced percutaneous injury rates compared with conventional devices. Activation rates varied according to ease of use, healthcare worker preference for ESIPDs, perceived “patient adverse events,” and device-specific training.
Device-specific features and healthcare worker training and involvement in the selection of ESIPDs affect the activation rates for ESIPDs and therefore their efficacy. The implementation of ESIPDs is a useful measure in a comprehensive program to reduce percutaneous injuries associated with phlebotomy procedures.
We present a 42-year-old male with botryomycosis initially presenting with left-sided proptosis due to an infraorbital mass. A biopsy through an anterior orbitotomy yielded indeterminate histopathology. The patient later developed a similar oral lesion which was biopsied and found to be botryomycosis. The oral lesion recurred after initial surgical treatment, but responded to antibiotic therapy. Discussion of this case along with a review of the literature is presented to offer guidelines for recognition and managment of this rare disorder.
Drawing on a survey of 406 British home owners in France, this study examines the origins, destinations and reasons for purchasing homes in rural France. In doing so it compares first home retired households with their pre-retirement counterparts and with second home owners who are retired. No notable differences are found in the geographical distribution or reasons for selecting home locations between these groups. However, patterns of retirement migration to France do appear to differ from intra-national long-distance migration within Britain and North America. Pointers to these differences are given and suggestions for future research are made. In addition, despite family visits and the friendship that people find in their recipient French communities, it is suggested that potential problems could arise for residents in relatively isolated rural communes. More research is needed to assess whether the positive attractions that are drawing retirement migrants from Britain to France will outweigh the negative consequences of their new home location.
A team of seven anthropologists conducted a coordinated, cross- cultural investigation to examine how structural and cultural variables shape the strategies people employ to assure themselves a secure old age. Central to the investigation was the goal of determining how people in the societies involved (Hong Kong, the United States, Ireland, and Botswana) perceive old age and its place in the adult life course, e.g. whether they view old age as an improvement or a decrement compared with other stages of life and the characteristics on which they base their views. The seven sites were selected to ensure broad representation in terms of the key structural variables of scale, complexity, subsistence pattern, residential mobility, and population structure. Both across and within sites people differed in their willingness and ability to discuss the concept of the life course. We attribute this variation to five factors: (i) characteristics of the social field, (2) education, (3) cultural salience of age categorisation, (4) predictability of life events, and (5) variability in timing of normative social or work roles.