2,755 research outputs found
Book Reviews
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66290/1/j.1752-7325.1985.tb01140.x.pd
PARASITES FROM HUMAN COPROLITES FROM MEXICO ZOONOTIC AND HUMAN PARASITES OF INHABITANTS OF CUEVA DE LOS MUERTOS CHIQUITOS, RIO ZAPE VALLEY, DURANGO, MEXICO.
We present the first reconstruction of the parasitoses among the people of the Loma San Gabriel culture, as represented by 36 coprolites excavated from the Cueva de los Muertos Chiquitos in Durango, Mexico. The coprolites date to approximately 1,400-yr-ago. Species identified based on eggs recovered include the trematode Echinostoma sp., the tapeworms Hymenolepis sp. and Dipylidium caninum, and the nematodes Ancylostoma duodenale, Enterobius vermicularis, and Trichuris trichiura. After rehydration and screening, 2 methods were used to recover eggs from these samples including spontaneous sedimentation and flotation. Samples were analyzed by 3 different laboratories for independent verification and comparison of methods. Spontaneous sedimentation resulted in the discovery of hymenolepidid eggs that were not found with flotation. Sedimentation was a more-sensitive indicator of prevalence as well. The modified method of flotation permitted estimation of egg concentration and resulted in the detection of a few specimens not found by sedimentation. The results of both methods showed that 19 (of 36) coprolites contained helminth eggs. Our results detected the presence of pathogenic helminths including hookworms and whipworms. The cestodes found do not cause severe pathology in humans. The early dates of hookworm and whipworm, relative to other findings in the southwest United States, indicate that these parasites arrived relatively late in prehistory in Arizona and New Mexico, probably moving into the area with travelers from Mesoamerica
Argument-Driven Engineering in Middle School Science: An Exploratory Study of Changes in Engineering Identity Over an Academic Year
The goal of this study was to examine how the use of a new instructional model is related to changes in middle school students’ engineering identity. The intent of this instructional model, which is called argument-driven engineering (ADE), is to give students opportunities to design and critique solutions to meaningful problems using the core ideas and practices of science and engineering. The model also reflects current recommendations found in the literature for supporting the development or maintenance of engineering identity. This study took place in the context of an eighth-grade science classroom in order to explore how middle school students’ engineering identities change over time as they become more familiar with engineering core ideas and practices. One hundred students participated in this study. These students completed three design tasks during the school year that were created using the ADE instructional model. These students also completed a survey that was designed to measure two important aspects of an engineering identity (recognition and interest) at three different time points. The results of a hierarchical linear modeling analysis suggest that students’ ideas about how they view themselves and others view them in terms of engineering did not change over time and their reported interest decreased from one survey to the next. The difficulty of the design tasks and the ways teachers enacted the instructional model are proposed as potential explanations for this counterintuitive finding
High Pressure Static and Time-Resolved X-Ray Studies of Inverse Phases in Cholesterol / Lipid Mixtures
Recommended from our members
Gladstone and Scott: Family, identity, and nation
In the 175 years since his death, Walter Scott has regularly been hailed as an influence by politicians. Amongst the poet-novelist's nineteenth-century political admirers, William Ewart Gladstone was possibly the most ardent, genuine, and significant. Scott's poems and novels were amongst the earliest texts Gladstone read; he read no works (in English), except the Bible, so consistently or completely over such a length of time. They offered him a plethora of inspirations, ideas, and language, which he imbibed and appropriated into his public and private lives. His concept of self, his understanding of family, and his sense of home, were all forged and conducted within a Scottian frame of reference. Scott's life and works also crucially influenced Gladstone's political understanding of the Scottish nation and its people, and his conception of how he could best serve their political interests. This article casts new light on an important and influential relationship in Gladstone's life, establishing that it was neither the superficial and recreational association some have described, nor simply a ploy of an astute politician. The article falls into three parts. The first elucidates how Gladstone's consumption of Scott's writings was seminal in the formation of his private identity, both individual and familial. The second explains how Gladstone's readings of Scott fitted into the specific and serious character of his other reading and knowledge-gathering, and the third shows how the details of Gladstone's response to Scott related to the broader intellectual and cultural context of his public life. By placing Gladstone within his Scottish context, this article shows how frequently and significantly his private and public worlds intersected
Before the Pandemic Ends: Making Sure This Never Happens Again
Introduction
On 30 January 2020, the World Health Organization (WHO) declared a Global Health Emergency of international concern attendant to the emergence and spread of SARS-CoV-2, nearly two months after the first reported emergence of human cases in Wuhan, China. In the subsequent two months, global, national and local health personnel and infrastructures have been overwhelmed, leading to suffering and death for infected people, and the threat of socio-economic instability and potential collapse for humanity as a whole. This shows that our current and traditional mode of coping, anchored in responses after the fact, is not capable of dealing with the crisis of emerging infectious disease. Given all of our technological expertise, why is there an emerging disease crisis, and why are we losing the battle to contain and diminish emerging diseases?
Part of the reason is that the prevailing paradigm explaining the biology of pathogen-host associations (coevolution, evolutionary arms races) has assumed that pathogens must evolve new capacities - special mutations – in order to colonize new hosts and produce emergent disease (e.g. Parrish and Kawaoka, 2005). In this erroneous but broadly prevalent view, the evolution of new capacities creates new opportunities for pathogens. Further, given that mutations are both rare and undirected, the highly specialized nature of pathogen-host relationships should produce an evolutionary firewall limiting dissemination; by those definitions, emergences should be rare (for a historical review see Brooks et al., 2019). Pathogens, however, have become far better at finding us than our traditional understanding predicts. We face considerable risk space for pathogens and disease that directly threaten us, our crops and livestock – through expanding interfaces bringing pathogens and hosts into increasing proximity, exacerbated by environmental disruption and urban density, fueled by globalized trade and travel. We need a new paradigm that explains what we are seeing.
Additional section headers:
The Stockholm Paradigm
The DAMA Protocol
A Sense of Urgency and Long-Term Commitment
Reference
Recommended from our members
Quantifying particle size and turbulent scale dependence of dust uplift in the Sahara using aircraft measurements
The first size-resolved airborne measurements of dust fluxes and the first dust flux measurements from the central Sahara are presented and compared with a parameterization by Kok (2011a). High-frequency measurements of dust size distribution were obtained from 0.16 to 300 µm diameter, and eddy covariance fluxes were derived. This is more than an order of magnitude larger size range than previous flux estimates. Links to surface emission are provided by analysis of particle drift velocities. Number flux is described by a −2 power law between 1 and 144 µm diameter, significantly larger than the 12 µm upper limit suggested by Kok (2011a). For small particles, the deviation from a power law varies with terrain type and the large size cutoff is correlated with atmospheric vertical turbulent kinetic energy, suggesting control by vertical transport rather than emission processes. The measured mass flux mode is in the range 30–100 µm. The turbulent scales important for dust flux are from 0.1 km to 1–10 km. The upper scale increases during the morning as boundary layer depth and eddy size increase. All locations where large dust fluxes were measured had large topographical variations. These features are often linked with highly erodible surface features, such as wadis or dunes. We also hypothesize that upslope flow and flow separation over such features enhance the dust flux by transporting large particles out of the saltation layer. The tendency to locate surface flux measurements in open, flat terrain means these favored dust sources have been neglected in previous studies
Assessing the Cost of Global Biodiversity and Conservation Knowledge
Knowledge products comprise assessments of authoritative information supported by standards, governance, quality control, data, tools, and capacity building mechanisms. Considerable resources are dedicated to developing and maintaining knowledge products for biodiversity conservation, and they are widely used to inform policy and advise decision makers and practitioners. However, the financial cost of delivering this information is largely undocumented. We evaluated the costs and funding sources for developing and maintaining four global biodiversity and conservation knowledge products: The IUCN Red List of Threatened Species, the IUCN Red List of Ecosystems, Protected Planet, and the World Database of Key Biodiversity Areas. These are secondary data sets, built on primary data collected by extensive networks of expert contributors worldwide. We estimate that US116–204 million), plus 293 person-years of volunteer time (range: 278–308 person-years) valued at US12–16 million), were invested in these four knowledge products between 1979 and 2013. More than half of this financing was provided through philanthropy, and nearly three-quarters was spent on personnel costs. The estimated annual cost of maintaining data and platforms for three of these knowledge products (excluding the IUCN Red List of Ecosystems for which annual costs were not possible to estimate for 2013) is US6.2–6.7 million). We estimated that an additional US12 million. These costs are much lower than those to maintain many other, similarly important, global knowledge products. Ensuring that biodiversity and conservation knowledge products are sufficiently up to date, comprehensive and accurate is fundamental to inform decision-making for biodiversity conservation and sustainable development. Thus, the development and implementation of plans for sustainable long-term financing for them is critical
MULTI-TEMPORAL AND MULTI-PLATFORM AGRICULTURAL LAND COVER CLASSIFICATION IN SOUTHEASTERN MICHIGAN
ABSTRACT We investigated the capabilities of multi-temporal and multi-platform remotely sensed imagery to differentiate crop types in the 14,600 ha Upper Tiffin watershed in southeastern Michigan, a primarily agricultural area. We focused on extracting signatures for corn, soybeans, wheat, alfalfa, and grasses as the major crops for the area. Input data included Landsat 5 TM, Terra/MODIS, and ASTER imagery for different parts of the 2004 and 2005 agricultural growing season. MODIS was selected to address the problems with obtaining sufficient repeat coverage of Landsat data during the growing season. We used both pixel-based and object-oriented classification techniques to assess the value of different techniques in leading to more useful agricultural land cover classifications. To contrast with these classification techniques, we predicted crop distributions using MODIS NDVI time-series profiles. ASTER data were investigated to see if its additional high-resolution bands and its multi-angle instruments could provide supplementary classification information. State and Federal agencies are active in the Upper Tiffin study area because of known problems with sediment and nutrient loading in local waterways. The Natural Resource Conservation Service (NRCS), part of the United States Department of Agriculture, used the results to understand how different land uses were affecting local water quality, and how the problems could be addressed
- …