2,812 research outputs found
Resection of Brainstem Cavernous Malformations: Pearls and Pitfalls for Minimizing Complications.
No full textBACKGROUND: Surgical management of brainstem cavernous malformations (CMs) is a controversial topic in the field of neurosurgery. These lesions have a propensity to hemorrhage, thereby disrupting surrounding brainstem eloquence.
METHODS: This article provides the personal reflections of the senior author and a narrative literature review on resection of brainstem CMs.
RESULTS: Here we discuss the indications for microsurgery, microsurgical techniques and nuances, and perioperative management considerations necessary to minimize complications during resection of brainstem CMs, which are lesions of venous origin.
CONCLUSIONS: The natural history of the lesion, risk of future hemorrhage, and potential for symptom resolution should be carefully considered when planning to resect brainstem CMs. Nuanced microsurgical techniques with minimal disruption of normal tissues provide the best chance of satisfactory outcomes
Comparison of several author indices for gauging academic productivity
No full textBackground
Many author indices exist to gauge academic productivity. Several of these indices are calculated based upon an author's scholarly publication record, but the measurement methodology to calculate each index varies considerably, and the precise function being used, as well as the end result, is often complex and difficult to assess.
Method
Two straightforward methods to weigh author productivity from the publication and citation record were evaluated as possible means for providing a clearer assessment of scholarly activity. The author characteristic index (termed c-index) assigns author rank for each publication based upon author position. The characteristic prime (c') -index normalizes author rank from author position, so that the total weight per publication is unity. The top 10 scholars with keyword 'celiac disease' in the Google Scholar database were then assessed using these metrics. Rankings according to total number of publications, h-index, and c- and c'-indices were compared, then tabulated along with total papers included for assessment, and mean values per paper for author position, number of authors, citations, and year of publication.
Results
The order of the top ten authors with keyword 'celiac disease' varied substantially depending upon whether the h-index, c-index, or c'-index was used as a gauge. The characteristic indices assign credit to authors according to their position in an author list. The affiliated metrics provided a more complete picture of scholarly activity.
Conclusions
Academic achievement by scholars, based upon quantitative publication characteristics, has recently become of interest for evaluating job candidates, for determining work performance, and for bestowing awards and honors. The characteristic indices as described herein are readily calculated and interpreted, and may improve the assessment of scholarly activity
Groups unaware of food recall: policy implications
No full textOn September 14, 2006, the U.S. Food and Drug Administration (FDA) issued an advisory warning against the consumption of fresh spinach because of suspected contamination with E. coli O157:H71. Following the advisory, a series of voluntary recalls were initiated nationwide, beginning with products from Natural Selection Foods, LLC, of San Juan Bautista, California, which produced bagged fresh spinach under 30 brand names. Fresh spinach was quickly removed from store shelves and restaurant menus.
Because of the serious nature of the risk posed by exposure to E. coli O157:H7, both the FDA and the produce industry carried out aggressive information campaigns to alert the public that they should not eat fresh spinach. In response, the recall received substantial media attention, resulting in extensive coverage in both newspapers and on television news broadcasts.
The objective of this study was to examine which groups of people were most likely to be unaware of the fresh spinach recall and therefore at risk for consuming contaminated spinach.
The study used a nationally representative telephone survey of 1,200 Americans, conducted from November 8-29, 2006.
The results indicated that the majority (87%) of Americans were aware of the spinach recall. However, awareness was not uniformly distributed across the population. While only 13% of Americans were unaware of the recall overall, 22% of African Americans, 23% of the Hispanic population, 21% of Americans age 18-34 and 16% of males reported that they hadn’t heard or read about the spinach recall.
As consuming spinach prior to the recall was associated with awareness of the recall, this variable was controlled for in regression analyses. However, even after controlling for prior spinach consumption, non-Whites, people of Hispanic origin, young adults (18-34 years old) and males were significantly more likely to be unaware of the spinach recall (Table 1).
A second logistic regression model found that those age 55 and older were no more or less likely to know about the recall than those younger than 55.Poster presented August 6, 2008 to the 95th annual meeting of the International Association for Food Protection, Columbus, OhioPeer reviewe
Understanding Consumer Interest in Organics: Production Values vs. Purchasing Behavior
No full textExtensive research exists on who does or might purchase organic food products, however little research has addressed either who values organic production methods when deciding what to eat, and correspondingly, who does not purchase organics regularly. This paper reports that values about organic farming often do not translate into corresponding stated preferences about organic food consumption behavior. The paradox is examined within the context of the consumers’ sociodemographic characteristics as well as through opinions and preferences related to food in their lives.
Results show that consumer claims of buying organics and placing importance on organic production systems when deciding what to eat are highly correlated (.472 at 1% significance level; p<. 001). Organic consumers, however, comprise only slightly more than one quarter (27%) of the highly enthusiastic proponents of organic production methods. Our results corroborate existing research that well-educated persons and those who are primary household shoppers purchase organics most frequently. Additionally, women and those who are older, have higher incomes, and are more liberal, as well as respondents who claim food production knowledge also tend to buy organic food regularly.
Regression and factor analysis show that those who value organic production systems when deciding what to eat may be ranked in the following order: the religiously observant, older and female respondents, persons of color, and those who claim food production knowledge. Results show that many of these organic system proponents are under-represented as buyers, in particular: the religiously observant, those for whom food plays an integral role in their lives, the less educated, and lower income and older respondents. More attention should be directed to people who value organic production systems yet do not purchase organics. This will enhance understanding of the transaction barriers that impede consumer participation in the organic market. How this population values organic production systems also has implications for the development of public policy related to sustainable and organic agriculture.Peer reviewe
Methods Used by Dr. R. K. Benjamin, and Other Mycologists, to Isolate Zygomycetes
No full textThe methods that Dr. Richard K. Benjamin used to isolate Zygomycetes are discussed. These processes involved the following five steps: (1) collection, (2) plating, (3) isolation, (4) culture, and (5) maintenance. Additional methods, materials, and modifications used to isolate Zygomycetes are summarized. The author considers the flattening of the aerial hyphae onto the substrate of the faster- and higher-growing Mucorales for several consecutive days to be the critical step in isolating species of Coemansia, Piptocephalis, Syncephalis, and Dimargaritales. The methods used by other scholars to isolate, culture, and study many taxa in Zygomycetes also are discussed
An Improved Homomorphism Preservation Theorem From Lower Bounds in Circuit Complexity
No full textPrevious work of the author [Rossmann'08] showed that the Homomorphism Preservation Theorem of classical model theory remains valid when its statement is restricted to finite structures. In this paper, we give a new proof of this result via a reduction to lower bounds in circuit complexity, specifically on the AC0 formula size of the colored subgraph isomorphism problem. Formally, we show the following: if a first-order sentence of quantifier-rank k is preserved under homomorphisms on finite structures, then it is equivalent on finite structures to an existential-positive sentence of quantifier-rank poly(k). Quantitatively, this improves the result of [Rossmann'08], where the upper bound on quantifier-rank is a non-elementary function of k
Erratum to: Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis
No full textIn the article “Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis,” an author was missing. Ana Maseda should be listed as the 11th author. The correct author list is: Benjamin Kye Jyn Tan, Ryan Eyn Kidd Man, Alfred Tau Liang Gan, Eva K Fenwick, Varshini Varadaraj, Bonnielin K Swenor, Preeti Gupta, Tien Yin Wong, Caterina Trevisan, Laura Lorenzo-López, Ana Maseda, José Carlos Millán-Calenti, Carla Helena Augustin Schwanke, Ann Liljas, Soham Al Snih, Yasuharu Tokuda, Ecosse Luc Lamoureux. This error has been corrected
Tagging of Biomedical Articles on CiteULike: A Comparison of User, Author and Professional Indexing
No full textThis paper examines the context of online indexing from the viewpoint of three different groups: users, authors, and professional indexers. User tags, author keywords and descriptors were collected from academic journal articles, which were both indexed in Pubmed and tagged on CiteULike, and analysed. Descriptive statistics, informetric measures, and thesaural term comparison shows that there are important differences in the use of keywords between the three groups in addition to similarities which can be used to enhance support for search and browse. While tags and author keywords were found that matched descriptors exactly, other terms which did not match but provided important expansion to the indexing lexicon were found. These additional terms could be used to enhance support for searching and browsing in article databases as well as to provide invaluable data for entry vocabulary and emergent terminology for regular updates to indexing systems. Additionally, the study suggests that tags support organisation by association to task, projects and subject while making important connections to traditional systems which classify into subject categories
Hot playgrounds and children's health: a multiscale analysis of surface temperatures in Arizona, USA
No full textabstract: Objectives: To provide novel quantification and advanced measurements of surface temperatures (Ts) in playgrounds, employing multiple scales of data, and provide insight into hot-hazard mitigation techniques and designs for improved environmental and public health. Methods: We conduct an analysis of Ts in two Metro-Phoenix playgrounds at three scales: neighborhood (1 km resolution), microscale (6.8 m resolution), and touch-scale (1 cm resolution). Data were derived from two sources: airborne remote sensing (neighborhood and microscale) and in situ (playground site) infrared Ts (touch-scale). Metrics of surface-to-air temperature deltas (Ts–a) and scale offsets (errors) are introduced. Results: Select in situ Ts in direct sunlight are shown to approach or surpass values likely to result in burns to children at touch-scales much finer than Ts resolved by airborne remote sensing. Scale offsets based on neighbourhood and microscale ground observations are 3.8 ◦C and 7.3 ◦C less than the Ts–a at the 1 cm touch-scale, respectively, and 6.6 ◦C and 10.1 ◦C lower than touch-scale playground equipment Ts, respectively. Hence, the coarser scales underestimate high Ts within playgrounds. Both natural (tree) and artificial (shade sail) shade types are associated with significant reductions in Ts. Conclusions: A scale mismatch exists based on differing methods of urban Ts measurement. The sub-meter touch-scale is the spatial scale at which data must be collected and policies of urban landscape design and health must be executed in order to mitigate high Ts in high-contact environments such as playgrounds. Shade implementation is the most promising mitigation technique to reduce child burns, increase park usability, and mitigate urban heating.Corresponding Author:
Jennifer K. Vanos
Texas Tech University
[email protected]
Food recalls and food safety perceptions: The September 2006 spinach recall case
No full textThis study analyzes public perceptions on food safety using a national survey conducted soon after the nationwide spinach recall (November 2006). We explore relationships between peoples’ perceived risks of food contamination (spinach in this case) and their trust in the institutions in charge of safeguarding/ensuring safety. Finally, we explore relationships between individual observance of basic good food handling practices and food safety. Trust in institutions through which food passes and regulatory agencies were shown to be critical in determining food safety perceptions. For example, skepticism with which the public views food corporations (processors, transporters or retailers) impacted food safety perceptions negatively. On the other, confidence in the USDA as a regulatory agent was viewed positively and hence contributed toward viewing the four types of spinach as safe for consumption.Agribusiness and Applied Economics Report No. 602, May 2007, North Dakota State Universit
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