A Theory of the Acquisition of Episodic Memory

Case-based reasoning (CBR) has been viewed by many as just a methodology for building systems, but the foundations of CBR are psychological theories. Dynamic Memory (Schank, 1982) was the first attempt to describe a theory for learning in computers and people, based on particular forms of data structures and processes, that nowadays are widely used in a variety of forms in CBR. In addition to being useful for system building, CBR provides a way of discussing a range of issues concerned with cognition. This focus on the practical uses of CBR has deflected attention from the need to develop further the underlying theory. In particular, the issue of knowledge acquisition, in not adequately handled by the existing theory. This paper discusses this theoretical weakness and then proposes an enhanced model of learning which is compatible with the CBR paradigm

Free Radicals in Superfluid Liquid Helium Nanodroplets: A Pyrolysis Source for the Production of Propargyl Radical

An effusive pyrolysis source is described for generating a continuous beam of radicals under conditions appropriate for the helium droplet pick-up method. Rotationally resolved spectra are reported for the $\nu_1$ vibrational mode of the propargyl radical in helium droplets at 3322.15 cm$^{-1}$. Stark spectra are also recorded that allow for the first experimental determination of the permanent electric dipole moment of propargyl, namely -0.150 D and -0.148 D for ground and excited state, respectively, in good agreement with previously reported ab initio results of -0.14 D [1]. The infrared spectrum of the $\nu_1$ mode of propargyl-bromide is also reported. The future application of these methods for the production of novel radical clusters is discussed

Pulmonary bullet embolism – a safe treatment strategy of a potentially fatal injury: a case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Quaternary geology of the Northern Great Plains

The Great Plains physiographic province lies east of the Rocky Mountains and extends from southern Alberta and Saskatchewan nearly to the United States-Mexico border. This chapter covers only the northern part of the unglaciated portion of this huge region, from Oklahoma almost to the United StatesCanada border, a portion that herein will be referred to simply as the Northern Great Plains (Fig. 1). This region is in the rain shadow of the Rocky Mountains. Isoheyets are roughly longitudinal, and mean annual precipitation decreases from about 750 mm at the southeastern margin to less than 380 mm in the western and northern parts (Fig. 2). Winters typically are cold with relatively little precipitation, mostly as snow; summers are hot with increased precipitation, chiefly associated with movement of Pacific and Arctic air masses into warm, humid air masses from the Gulf of Mexico. Vegetation is almost wholly prairie grassland, due to the semiarid, markedly seasonal climate. The Northern Great Plains is a large region of generally low relief sloping eastward from the Rocky Mountains toward the Missouri and Mississippi Rivers. Its basic bedrock structure is a broad syncline, punctuated by the Black Hills and a few smaller uplifts, and by structural basins such as the Williston, Powder River, and Denver-Julesburg Basins (Fig. 3). Its surface bedrock is chiefly Cretaceous and Tertiary sediments, with small areas of older rocks in the Black Hills, central Montana, and eastern parts of Wyoming, Kansas, and Oklahoma. During the Laramide orogeny (latest Cretaceous through Eocene), while the Rocky Mountains and Black Hills were rising, synorogenic sediments (frequently with large amounts of volcanic ash from volcanic centers in the Rocky Mountains) were deposited in the subsiding Denver-Julesburg, Powder River, and other basins. From Oligocene to Miocene time, sedimentation generally slowed with declining tectonism and volcanism in the Rocky Mountains. However, since the later Miocene, epeirogenic uplift, probably associated with the East Pacific Rise, affected the Great Plains and particularly the Rocky Mountains. During the last 10 m.y. the Rocky Mountain front has risen 1.5 to 2 km, and the eastern margin of the Great Plains 100 to 500 m (Gable and Hatton, 1983), with half to one-quarter of these amounts during the last 5 m.y. Thus, during the later Miocene the Great Plains became a huge aggrading piedmont sloping gently eastward from the Rocky Mountains and Black Hills, with generally eastward drainage, on which the Ogallala Formation and equivalents was deposited. The Ogallala underlies the High Plains Surface, the highest and oldest geomorphic surface preserved in this region. It has been completely eroded along some parts of the western margin of the region (e.g., the Colorado Piedmont), but eastward, it (and its equivalents, such as the Flaxville gravels in Montana) locally is preserved as caprock or buried by Quaternary sediments (Alden, 1924, 1932; Howard, 1960; Stanley, 1971, 1976; Pearl, 1971; Scott, 1982; Corner and Diffendal, 1983; Diffendal and Corner, 1984; Swinehart and others, 1985; Aber, 1985). During the Pliocene, regional aggradation slowly changed to dissection by the principal rivers. In the western part of the region the rivers flowed eastward, but the continental drainage divide Figure 3. Major bedrock structures of the Northern Great Plains. extended northeast from the Black Hills through central South Dakota, far south of its present position. The ancestral upper Missouri, Little Missouri, Yellowstone, and Cheyenne Rivers drained northeast to Hudson Bay, whereas the ancestral White, Platte, and Arkansas Rivers went to the Gulf of Mexico (Fig 4A). Their courses are marked by scattered surface and subsurface gravel remnants; in Montana and North Dakota, deposits of the preglacial Missouri River and its tributaries are buried deeply beneath glacial and other sediments (Howard, 1960; Bluemle, 1972)

Entrance Channel X-HF (X=Cl, Br, and I) Complexes studied by High-Resolution Infrared Laser Spectroscopy in Helium Nanodroplets

Rotationally resolved infrared spectra are reported for halogen atom - HF free radical complexes formed in helium nanodroplets. An effusive pyrolysis source is used to dope helium droplets with Cl, Br and I atoms, formed by thermal dissociation of Cl$_2$, Br$_2$ and I$_2$. A single hydrogen fluoride molecule is then added to the droplets, resulting in the formation of the X-HF complexes of interest. Analysis of the resulting spectra confirms that the observed species have $^2\Pi_{3/2}$ ground electronic states, consistent with the linear hydrogen bound structures predicted from theory. Stark spectra are also reported for these species, from which the permanent electric dipole moments are determined.Comment: 41 pages, 16 figures, 5 table

Audio computer-assisted self-interviewing (ACASI) may avert socially desirable responses about infant feeding in the context of HIV

BACKGROUND: Understanding infant feeding practices in the context of HIV and factors that put mothers at risk of HIV infection is an important step towards prevention of mother to child transmission of HIV (PMTCT). Face-to-face (FTF) interviewing may not be a suitable way of ascertaining this information because respondents may report what is socially desirable. Audio computer-assisted self-interviewing (ACASI) is thought to increase privacy, reporting of sensitive issues and to eliminate socially desirable responses. We compared ACASI with FTF interviewing and explored its feasibility, usability, and acceptability in a PMTCT program in Kenya. METHODS: A graphic user interface (GUI) was developed using Macromedia Authorware(® )and questions and instructions recorded in local languages Kikuyu and Kiswahili. Eighty mothers enrolled in the PMTCT program were interviewed with each of the interviewing mode (ACASI and FTF) and responses obtained in FTF interviews and ACASI compared using McNemar's χ(2 )for paired proportions. A paired Student's t-test was used to compare means of age, marital-time and parity when measuring interview mode effect and two-sample Student's t-test to compare means for samples stratified by education level – determined during the exit interview. A Chi-Square (χ(2)test) was used to compare ability to use ACASI by education level. RESULTS: Mean ages for intended time for breastfeeding as reported by ACASI were 11 months by ACASI and 19 months by FTF interviewing (p < 0.001). Introduction of complementary foods at ≤3 months was reported more frequently by respondents in ACASI compared to FTF interviews for 7 of 13 complementary food items commonly utilized in the study area (p < 0.05). More respondents reported use of unsuitable utensils for infant feeding in ACASI than in FTF interviewing (p = 0.001). In other sensitive questions, 7% more respondents reported unstable relationships with ACASI than when interviewed FTF (p = 0.039). Regardless of education level, respondents used ACASI similarly and majority (65%) preferred it to FTF interviewing mainly due to enhanced usability and privacy. Most respondents (79%) preferred ACASI to FTF for future interviewing. CONCLUSION: ACASI seems to improve quality of information by increasing response to sensitive questions, decreasing socially desirable responses, and by preventing null responses and was suitable for collecting data in a setting where formal education is low

The appended curve technique for deconvolutional analysis —method and validation

Deconvolutional analysis (DCA) is useful in correction of organ time activity curves (response function) for variations in blood activity (input function). Despite enthusiastic reports of applications of DCA in renal and cardiac scintigraphy, routine use has awaited an easily implemented algorithm which is insensitive to statistical noise. The matrix method suffers from the propagation of errors in early data points through the entire curve. Curve fitting or constraint methods require prior knowledge of the expected form of the results. DCA by Fourier transforms (FT) is less influenced by single data points but often suffers from high frequency artifacts which result from the abrupt termination of data acquisition at a nonzero value.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46829/1/259_2004_Article_BF00254393.pd

Genome-wide Analyses Identify KIF5A as a Novel ALS Gene

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe