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Showing papers by "University of Massachusetts Amherst published in 1993"


Journal ArticleDOI
29 Apr 1993-Nature
TL;DR: It is demonstrated that immature thymocytes lacking p53 die normally when exposed to compounds that may mimic T-cell receptor engagement and to glucocorticoids but are resistant to the lethal effects of ionizing radiation.
Abstract: The p53 tumour suppressor gene is the most widely mutated gene in human tumorigenesis. p53 encodes a transcriptional activator whose targets may include genes that regulate genomic stability, the cellular response to DNA damage, and cell-cycle progression. Introduction of wild-type p53 into cell lines that have lost endogenous p53 function can cause growth arrest or induce a process of cell death known as apoptosis. During normal development, self-reactive thymocytes undergo negative selection by apoptosis, which can also be induced in immature thymocytes by other stimuli, including exposure to glucocorticoids and ionizing radiation. Although normal negative selection involves signalling through the T-cell receptor, the induction of apoptosis by other stimuli is poorly understood. We have investigated the requirement for p53 during apoptosis in mouse thymocytes. We report here that immature thymocytes lacking p53 die normally when exposed to compounds that may mimic T-cell receptor engagement and to glucocorticoids but are resistant to the lethal effects of ionizing radiation. These results demonstrate that p53 is required for radiation-induced cell death in the thymus but is not necessary for all forms of apoptosis.

2,916 citations


Proceedings ArticleDOI
01 May 1993
TL;DR: Simulation results show that transactional memory matches or outperforms the best known locking techniques for simple benchmarks, even in the absence of priority inversion, convoying, and deadlock.
Abstract: A shared data structure is lock-free if its operations do not require mutual exclusion. If one process is interrupted in the middle of an operation, other processes will not be prevented from operating on that object. In highly concurrent systems, lock-free data structures avoid common problems associated with conventional locking techniques, including priority inversion, convoying, and difficulty of avoiding deadlock. This paper introduces transactional memory, a new multiprocessor architecture intended to make lock-free synchronization as efficient (and easy to use) as conventional techniques based on mutual exclusion. Transactional memory allows programmers to define customized read-modify-write operations that apply to multiple, independently-chosen words of memory. It is implemented by straightforward extensions to any multiprocessor cache-coherence protocol. Simulation results show that transactional memory matches or outperforms the best known locking techniques for simple benchmarks, even in the absence of priority inversion, convoying, and deadlock.

2,406 citations


Book
01 Jan 1993
TL;DR: The principles of the algorithms available for performing arithmetic operations in digital computers, described independently of specific implementation technology and within the same framework, are explained.
Abstract: This text explains the fundamental principles of algorithms available for performing arithmetic operations on digital computers. These include basic arithmetic operations like addition, subtraction, multiplication, and division in fixed-point and floating-point number systems as well as more complex operations such as square root extraction and evaluation of exponential, logarithmic, and trigonometric functions. The algorithms described are independent of the particular technology employed for their implementation.

1,174 citations


Journal ArticleDOI

1,082 citations


Proceedings ArticleDOI
01 Jun 1993
TL;DR: The LRU-K algorithm surpasses conventional buffering algorithms in discriminating between frequently and infrequently referenced pages, and adapts in real time to changing patterns of access.
Abstract: This paper introduces a new approach to database disk buffering, called the LRU-K method The basic idea of LRU-K is to keep track of the times of the last K references to popular database pages, using this information to statistically estimate the interarrival times of references on a page by page basis Although the LRU-K approach performs optimal statistical inference under relatively standard assumptions, it is fairly simple and incurs little bookkeeping overhead As we demonstrate with simulation experiments, the LRU-K algorithm surpasses conventional buffering algorithms in discriminating between frequently and infrequently referenced pages In fact, LRU-K can approach the behavior of buffering algorithms in which page sets with known access frequencies are manually assigned to different buffer pools of specifically tuned sizes Unlike such customized buffering algorithms however, the LRU-K method is self-tuning, and does not rely on external hints about workload characteristics Furthermore, the LRU-K algorithm adapts in real time to changing patterns of access

1,033 citations


Journal ArticleDOI
24 Nov 1993-JAMA
TL;DR: Among severity systems for intensive care patients, the MPM0 is the only model available for use at ICU admission and bothMPM0 and MPM24 are useful research tools and provide important clinical information when used alone or together.
Abstract: Objective. —To revise and update models in the Mortality Probability Model (MPM II) system to estimate the probability of hospital mortality among 19124 intensive care unit (ICU) patients that can be used for quality assessment within and among ICUs. Design and Setting. —Models developed and validated on consecutive admissions to adult medical and surgical ICUs in 12 countries. Patients. —A total of 12610 patients for model development, 6514 patients for model validation. Patients younger than 18 years and burn, coronary care, and cardiac surgery patients were excluded. Outcome Measure. —Vital status at hospital discharge. Results. —The admission model, MPM0, contains 15 readily obtainable variables. In developmental and validation samples it calibrated well (goodness-of-fit tests:P=.623 andP=.327, respectively, where a highPvalue represents good fit between observed and expected values) and discriminated well (area under the receiver operating characteristic curve=0.837 and 0.824, respectively). The 24-hour model, MPM24(developed on 10357 patients still in the ICU at 24 hours), contains five of the admission variables and eight additional variables easily ascertained at 24 hours. It also calibrated well (P=.764 andP=.231 in the developmental and validation samples, respectively) and discriminated well (area under the receiver operating characteristic curve=0.844 and 0.836 in the developmental and validation samples, respectively). Conclusions. —Among severity systems for intensive care patients, the MPM0is the only model available for use at ICU admission. Both MPM0and MPM24are useful research tools and provide important clinical information when used alone or together. (JAMA. 1993;270:2478-2486)

1,009 citations


Journal ArticleDOI
TL;DR: The relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century as mentioned in this paper, and the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling.
Abstract: I. Introduction A FUNCTIONAL relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century. In the case of bone, as observed with other cells and tissue, the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling. For many years, bone was defined anatomically and examined largely in a descriptive manner by ultrastructural analysis and by biochemical and histochemical methods. These studies provided the basis for our understanding of bone tissue organization and orchestration of the progressive recruitment, proliferation, and differentiation of the various cellular components of bone tissue. Now, complemented by an increased knowledge of molecular mechanisms that are associated with and regulate expression of genes encoding phenotypic compone...

973 citations


Journal ArticleDOI
01 Aug 1993
TL;DR: A rigorous proof of convergence of DP-based learning algorithms is provided by relating them to the powerful techniques of stochastic approximation theory via a new convergence theorem, which establishes a general class of convergent algorithms to which both TD() and Q-learning belong.
Abstract: Recent developments in the area of reinforcement learning have yielded a number of new algorithms for the prediction and control of Markovian environments. These algorithms, including the TD(λ) algorithm of Sutton (1988) and the Q-learning algorithm of Watkins (1989), can be motivated heuristically as approximations to dynamic programming (DP). In this paper we provide a rigorous proof of convergence of these DP-based learning algorithms by relating them to the powerful techniques of stochastic approximation theory via a new convergence theorem. The theorem establishes a general class of convergent algorithms to which both TD(λ) and Q-learning belong.

936 citations


Journal ArticleDOI
TL;DR: Profiles of the phospholipid ester-linked fatty acids indicated that both the anaerobic desaturase and the branched pathways for fatty acid biosynthesis were operative, and the 16S rRNA sequence indicated that this organism belongs in the delta proteobacteria.
Abstract: The gram-negative metal-reducing microorganism, previously known as strain GS-15, was further characterized. This strict anaerobe oxidizes several short-chain fatty acids, alcohols, and monoaromatic compounds with Fe(III) as the sole electron acceptor. Furthermore, acetate is also oxidized with the reduction of Mn(IV), U(VI), and nitrate. In whole cell suspensions, the c-type cytochrome(s) of this organism was oxidized by physiological electron acceptors and also by gold, silver, mercury, and chromate. Menaquinone was recovered in concentrations comparable to those previously found in gram-negative sulfate reducers. Profiles of the phospholipid ester-linked fatty acids indicated that both the anaerobic desaturase and the branched pathways for fatty acid biosynthesis were operative. The organism contained three lipopolysaccharide hydroxy fatty acids which have not been previously reported in microorganisms, but have been observed in anaerobic freshwater sediments. The 16S rRNA sequence indicated that this organism belongs in the delta proteobacteria. Its closest known relative is Desulfuromonas acetoxidans. The name Geobacter metallireducens is proposed.

913 citations


Journal ArticleDOI
TL;DR: The authors argue that the exclusive use of English in teaching ESL has come to be seen as a natural and commonsense practice which can be justified on pedagogical grounds, but it is rooted in a particular ideological perspective, rests on unexamined assumptions, and serves to reinforce inequities in the broader social order.
Abstract: Despite widespread opposition to the English Only movement, support for bilingual education, and advocacy for language rights, many U.S. ESL educators continue to uphold the notion that English is the only acceptable medium of communication within the confines of the ESL classroom. Although the exclusive use of English in teaching ESL has come to be seen as a natural and commonsense practice which can be justified on pedagogical grounds, this article argues that it is rooted in a particular ideological perspective, rests on unexamined assumptions, and serves to reinforce inequities in the broader social order. Evidence from research and practice is presented which suggests that the rationale used to justify English only in the classroom is neither conclusive nor pedagogically sound. Further, the article details a growing body of evidence indicating that L1 and/or bilingual options are not only effective but necessary for adult ESL students with limited L1 literacy or schooling and that use of students' linguistic resources can be beneficial at all levels of ESL. Accounts from a number of projects, including two with which the author has been involved, document a range of uses for the native language in both initial literacy and ESL instruction for adults. Finally, because the issue of language choice is so intimately linked with issues of power, the article calls for reconceptualizing the notion of expertise to legitimate the knowledge and experience of nontraditional experts from the communities of the learners.

829 citations


Journal ArticleDOI
TL;DR: In this paper, the authors make an analogy between images and statistical mechanics systems, where pixel gray levels and the presence and orientation of edges are viewed as states of atoms or molecules in a lattice-like physical system.
Abstract: We make an analogy between images and statistical mechanics systems. Pixel gray levels and the presence and orientation of edges are viewed as states of atoms or molecules in a lattice-like physical system. The assignment of an energy function in the physical system determines its Gibbs distribution. Because of the Gibbs distribution, Markov random field (MRF) equivalence, this assignment also determines an MRF image model. The energy function is a more convenient and natural mechanism for embodying picture attributes than are the local characteristics of the MRF. For a range of degradation mechanisms, including blurring, non-linear deformations, and multiplicative or additive noise, the posterior distribution is an MRF with a structure akin to the image model. By the analogy, the posterior distribution defines another (imaginary) physical system. Gradual temperature reduction in the physical system isolates low-energy states (‘annealing’), or what is the same thing, the most probable states under the Gib...

Journal ArticleDOI
TL;DR: Using historical, tree-ring and ice core data, the authors examined climatic variations during the period commonly called the "Little Ice Age", and found that unusually warm conditions have prevailed since the 1920s, probably related to a relative absence of major explosive volcanic eruptions and higher levels of greenhouse gases.
Abstract: Climatic changes resulting from greenhouse gases will be superimposed on natural climatic variations. High-resolution proxy records of past climate can be used to extend our perspective on regional and hemispheric changes of climate back in time by several hundred years. Using historical, tree-ring and ice core data, we examine climatic variations during the period commonly called the 'Little Ice Age'. The coldest conditions of the last 560 years were between AD 1570 and 1730, and in the nineteenth century. Unusually warm conditions have prevailed since the 1920s, probably related to a relative absence of major explosive volcanic eruptions and higher levels of greenhouse gases.

Journal ArticleDOI
11 Nov 1993-Nature
TL;DR: The results show that the SWI2 family DNA-dependent ATPase domain has functional con-servation between yeast and humans and suggest that a SWI/SNF protein complex is required for the activation of selective mammalian genes.
Abstract: SEQUENCE-SPECIFIC DNA binding activators of gene transcription may be assisted by SWI2(SNF2)1,2, which contains a DNA-depen-dent ATPase domain3. We have isolated a human complementary DNA encoding a 205K nuclear protein, BRG1, that contains extensive homology to SWI2 and Drosophila brahma4,5. We report here that a SWI2/BRG1 chimaera with the DNA-dependent ATPase domain replaced by corresponding human sequence restored normal mitotic growth and capacity for transcriptional activation to swi2& minus; yeast cells. Point mutation of the conserved ATP binding site lysine abolished this complementation. This mutation in SW12 exerted a dominant negative effect on transcription in yeast. A lysine to arginine substitution at the corresponding residue of BRG1 also generated a transcriptional dominant negative in human cells. BRG1 is exclusively nuclear and present in a high Mr complex of about 2 & times; 106. These results show that the SWI2 family DNA-dependent ATPase domain has functional con-servation between yeast and humans and suggest that a SWI/SNF protein complex is required for the activation of selective mammalian genes.

Journal ArticleDOI
TL;DR: A review of coagulation in drinking water treatment is presented in this article, which emphasizes the importance of raw water chemistry, natural organic matter (NOM) concentration and type, and the chemistry of Coagulants.

Journal ArticleDOI
TL;DR: This paper explores the issues in real-time database systems and presents an overview of the state of the art, and examines different approaches to resolving contention over data and processing resources.
Abstract: Data in real-time databases has to be logically consistent as well as temporally consistent. The latter arises from the need to preserve the temporal validity of data items that reflect the state of the environment that is being controlled by the system. Some of the timing constraints on the transactions that process real-time data come from this need. These constraints, in turn, necessitate time-cognizant transaction processing so that transactions can be processed to meet their deadlines.

Journal ArticleDOI
TL;DR: Comparing the patterns of cell death displayed by T cells and the intersegmental muscles is compared and it is found that they differ in terms of cell-surface morphology, nuclear ultrastructure, DNA fragmentation, and polyubiquitin gene expression.
Abstract: During development, large numbers of cells die by a nonpathological process referred to as programmed cell death. In many tissues, dying cells display similar changes in morphology and chromosomal DNA organization, which has been termed apoptosis. Apoptosis is such a widely documented phenomenon that many authors have assumed all programmed cell deaths occur by this process. Two well-characterized model systems for programmed cell death are (i) the death of T cells during negative selection in the mouse thymus and (ii) the loss of intersegmental muscles of the moth Manduca sexta at the end of metamorphosis. In this report we compare the patterns of cell death displayed by T cells and the intersegmental muscles and find that they differ in terms of cell-surface morphology, nuclear ultrastructure, DNA fragmentation, and polyubiquitin gene expression. Unlike the T cells, which are known to die via apoptosis, we find that the intersegmental muscles display few of the features that characterize apoptosis. These data suggest that more than one cell death mechanism is used during development.

Journal ArticleDOI
TL;DR: A new battery model developed for use in time series performance models of hybrid energy systems, based on the approach of chemical kinetics, which is specifically concerned with the apparent change in capacity as a function of charge and discharge rates.

Proceedings Article
11 Jul 1993
TL;DR: This paper presents a formalization of the bidding and awarding decision process that was left undefined in the original contract net task allocation protocol, based on marginal cost calculations based on local agent criteria.
Abstract: This paper presents a formalization of the bidding and awarding decision process that was left undefined in the original contract net task allocation protocol This formalization is based on marginal cost calculations based on local agent criteria In this way, agents having very different local criteria (based on their selfinterest) can interact to distribute tasks so that the network as a whole functions more effectively In this model, both competitive and cooperative agents can interact In addition, the contract net protocol is extended to allow for clustering of tasks, to deal with the possibility of a large number of announcement and bid messages and to effectively handle situations, in which new bidding and awarding is being done during the period when the results of previous bids are unknown The protocol is verified by the TRACONET (TRAnsportation Cooperation' NET) system, where dispatch centers of different companies cooperate automatically in vehicle routing The implementation is asynchronous and truly distributed, and it provides the agents extensive autonomy The protocol is discussed in detail and test results with real data are presented

Proceedings Article
11 Jul 1993
TL;DR: Using AutoSlog, a system that automatically builds a domain-specific dictionary of concepts for extracting information from text, a dictionary for the domain of terrorist event descriptions was constructed in only 5 person-hours and the overall scores were virtually indistinguishable.
Abstract: Knowledge-based natural language processing systems have achieved good success with certain tasks but they are often criticized because they depend on a domain-specific dictionary that requires a great deal of manual knowledge engineering. This knowledge engineering bottleneck makes knowledge-based NLP systems impractical for real-world applications because they cannot be easily scaled up or ported to new domains. In response to this problem, we developed a system called AutoSlog that automatically builds a domain-specific dictionary of concepts for extracting information from text. Using AutoSlog, we constructed a dictionary for the domain of terrorist event descriptions in only 5 person-hours. We then compared the AutoSlog dictionary with a hand-crafted dictionary that was built by two highly skilled graduate students and required approximately 1500 person-hours of effort. We evaluated the two dictionaries using two blind test sets of 100 texts each. Overall, the AutoSlog dictionary achieved 98% of the performance of the hand-crafted dictionary. On the first test set, the AutoSlog dictionary obtained 96.3% of the performance of the hand-crafted dictionary. On the second test set, the overall scores were virtually indistinguishable with the AutoSlog dictionary achieving 99.7% of the performance of the handcrafted dictionary.

Journal ArticleDOI
TL;DR: It is the collective view that the TIP has played, and will continue to play, a pivotal role in elucidation of the function of MEL in the photoperiodic control of seasonal mammalian responses and that the duration of the MEL signal is the critical parameter of the nocturnal secretion profile of the hormone for the phot operable control of several seasonally adaptive responses in mammalian species as diverse as hamsters and sheep.
Abstract: This review summarizes the evidence showing that the duration of the nocturnal secretory profile of pineal melatonin (MEL) is critical for eliciting seasonally appropriate reproductive physiological and behavioral responses in mammals. We review experiments using the timed infusion paradigm (TIP) to deliver MEL either systemically or centrally to pinealectomized hamsters and sheep. In this paradigm, MEL is infused, usually once daily, for a specific number of hours and at a predetermined time of day. This experimental strategy tests most directly those features of the MEL signal that are necessary to trigger photoperiodic responses. The data suggest that the duration of the MEL stimulation is the critical feature of the MEL signal for both inhibitory and stimulatory effects of the hormone on the photoperiodic control of reproductive development in juvenile Siberian hamsters, and for the photoperiodic control of reproductive and metabolic responses in adult Siberian and Syrian hamsters and sheep. The use of the TIP reveals the importance of the frequency of the signal presentation of MEL and suggests the importance of a period of low-to-absent circulating concentrations of the hormone. The TIP also reveals that the characteristics of the MEL signal that regulate male sexual behavior are similar to those that are critical for reproductive and metabolic responses in Syrian hamsters. We summarize the locations of possible functional MEL target sites identified by combining the TIP with traditional brain lesion techniques. Evidence from such studies suggests that the integrity of the suprachiasmatic nucleus (SCN) region in Siberian hamsters and the anterior hypothalamus in Syrian hamsters is necessary for the response to short-day MEL signals. The TIP has been used to deliver MEL to putative target sites for the hormone in the brain of juvenile and adult Siberian hamsters. The results of these preliminary experiments suggest that the regions of specific MEL binding in this species, especially the SCN, are effective sites where MEL may stimulate short-day-type responses. In contrast, results from intracranial application of MEL in sheep suggest the medial basal hypothalamus as a critical site of action. Finally, we also discuss potential applications of the TIP for identification of brain MEL target sites, understanding of other photoperiodic phenomena and responses, and resolution of the cellular/molecular basis underlying the reception and interpretation of MEL signals.(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
TL;DR: In this article, the authors designed a set of lessons to deal with students' alternative conceptions in three areas of mechanics: static normal forces, frictional forces, and Newton's third law for moving objects.
Abstract: Lessons were designed to deal with students' alternative conceptions in three areas of mechanics: static normal forces, frictional forces, and Newton's third law for moving objects. Instructional techniques such as class discussions of the validity of an analogy between a target problem and an intuitive anchoring example, and forming a structured chain of intermediate bridging analogies were used. There were large differences in pre–posttest gains in favor of the experimental group. In formulating a model of learning processes that can explain these results, it is argued that (a) the lessons have a more complex structure than a simple model of analogy use; (b) rational methods using analogy and other plausible reasoning processes that are neither proof based nor directly empirical can play a very important role in science instruction; (c) much more effort than is usually allocated should be focused on helping students to make sense of an analogy; and (d) researchers and curriculum developers should be focusing at least as much attention on students' useful prior knowledge as they are on students' alternative conceptions.

Journal ArticleDOI
TL;DR: In this paper, the authors conceptualize direct mail as an implied social contract between marketers and consumers, and four attributes constitute the direct mail social contract: volume, targeting, compensation, and reach.
Abstract: The authors conceptualize direct mail as an implied social contract between marketers and consumers. Four attributes constitute the direct mail social contract: volume, targeting, compensation, and...

Journal ArticleDOI
15 Jan 1993-Science
TL;DR: A transfer RNA (tRNA) binding protein present in HeLa cell nuclear extracts was purified and identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which suggests that the protein may participate in RNA export.
Abstract: A transfer RNA (tRNA) binding protein present in HeLa cell nuclear extracts was purified and identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Studies with mutant tRNAs indicated that GAPDH recognizes both sequence and structural features in the RNA. GAPDH discriminated between wild-type tRNA and two tRNA mutants that are defective in nuclear export, which suggests that the protein may participate in RNA export. The cofactor nicotinamide adenine dinucleotide disrupted complex formation between tRNA and GAPDH and thus may share a common binding site with the RNA. Indirect immunofluorescence experiments showed that GAPDH is present in the nucleus as well as in the cytoplasm.

Journal ArticleDOI
TL;DR: The goals of the paper are to demonstrate that although non-standard, many of the important quantitative and qualitative properties of ordinary differential equations that hold under the standard conditions apply here as well, and to prove convergence for a class of numerical schemes designed to approximate solutions to a given variational inequality.
Abstract: The variational inequality problem has been utilized to formulate and study a plethora of competitive equilibrium problems in different disciplines, ranging from oligopolistic market equilibrium problems to traffic network equilibrium problems. In this paper we consider for a given variational inequality a naturally related ordinary differential equation. The ordinary differential equations that arise are nonstandard because of discontinuities that appear in the dynamics. These discontinuities are due to the constraints associated with the feasible region of the variational inequality problem. The goals of the paper are two-fold. The first goal is to demonstrate that although non-standard, many of the important quantitative and qualitative properties of ordinary differential equations that hold under the standard conditions, such as Lipschitz continuity type conditions, apply here as well. This is important from the point of view of modeling, since it suggests (at least under some appropriate conditions) that these ordinary differential equations may serve as dynamical models. The second goal is to prove convergence for a class of numerical schemes designed to approximate solutions to a given variational inequality. This is done by exploiting the equivalence between the stationary points of the associated ordinary differential equation and the solutions of the variational inequality problem. It can be expected that the techniques described in this paper will be useful for more elaborate dynamical models, such as stochastic models, and that the connection between such dynamical models and the solutions to the variational inequalities will provide a deeper understanding of equilibrium problems.

Journal ArticleDOI
26 Feb 1993-Science
TL;DR: The transcription and processing site of the fibronectin gene localized to the nuclear interior and was associated with larger transcript domains in over 88 percent of the cells, which support a view of nuclear function closely integrated with structure.
Abstract: Visualization of fibronectin and neurotensin messenger RNAs within mammalian interphase nuclei was achieved by fluorescence hybridization with genomic, complementary DNA, and intron-specific probes. Unspliced transcripts accumulated in one or two sites per nucleus. Fibronectin RNA frequently accumulated in elongated tracks that overlapped and extended well beyond the site of transcription. Splicing appears to occur directly within this RNA track, as evidenced by an unambiguous spatial separation of intron-containing and spliced transcripts. Excised introns for neurotensin RNA appear free to diffuse. The transcription and processing site of the fibronectin gene localized to the nuclear interior and was associated with larger transcript domains in over 88 percent of the cells. These results support a view of nuclear function closely integrated with structure.

Journal ArticleDOI
TL;DR: Here, Lawrence Schwartz and Barbara Osborne define the terms and ideas relevant to the study of cell death in a way that will be accessible to investigators from all fields.

Journal ArticleDOI
TL;DR: A recent investigation of color-sensory interactions in beverages has shown that color interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods.
Abstract: From birth, nature teaches us to make judgements on our environment based in large measure on color. As such, it plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Its role is elusive and difficult to quantify, however, which at times has placed color in a secondary role to the other sensory characteristics, a position not entirely consistent with the facts. Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods. Studies in the literature have used cross‐sectional population panels to study these effects, but a recent investigation of color‐sensory interactions in beverages has compared the response of a college age group with the response of a panel consisting of a mo...

Journal ArticleDOI
TL;DR: For instance, this article found that teenagers and young adults with attention deficit hyperactivity disorder (ADHD) have more motor vehicle citations and crashes and are more careless drivers than their normal peers.
Abstract: OBJECTIVE. To determine whether teenagers and young adults with attention deficit hyperactivity disorder (ADHD) have more motor vehicle citations and crashes and are more careless drivers than their normal peers. DESIGN. A comparison of two groups of teenagers and young adults (ADHD and normal) followed up 3 to 5 years after original diagnosis. SETTING. A university medical center clinic for ADHD patients. PATIENTS. Thirty-five subjects with ADHD and 36 control subjects between 16 and 22 years of age, all of whom were licensed drivers. MAIN OUTCOME MEASURES. Parent ratings of current symptoms of ADHD, oppositional defiant disorder, and conduct disorder, a survey of various negative driving outcomes, and a rating scale of driving behavior. RESULTS. Subjects with ADHD used less sound driving habits. This deficiency was associated with greater driving-related negative outcomes in all categories surveyed. Subjects with ADHD were more likely than control subjects to have had auto crashes, to have had more such crashes, to have more bodily injuries associated with such crashes, and to be at fault for more crashes than control subjects. They were also more likely to have received traffic citations and received more such citations than control subjects, particularly for speeding. The sub-group of teenagers with ADHD having greater comorbid oppositional defiant disorder and conduct disorder symptoms were at highest risk for such deficient driving skills/habits and negative driving-related outcomes. CONCLUSIONS. ADHD, and especially its association with oppositional defiant disorder/conduct disorder, is associated with substantially increased risks for driving among teenagers and young adults and worthy of attention when clinicians counsel such patients and their parents. Language: en

Journal ArticleDOI
TL;DR: This study has shown increases in total estrogen levels and amount of bioavailable estrogens in association with alcohol consumption in premenopausal women, and increased total estradiol levels in the peri-ovulatory phase suggest elevated absolute amounts of bio available estradio.
Abstract: Background Most epidemiologic studies of the relationship between alcohol consumption and breast cancer risk over the past decade have shown that persons who consume a moderate amount of alcohol are at 40%-100% greater risk of breast cancer than those who do not consume alcohol. Dose-response effects have been observed, but no causal relationship has been established. Purpose This study examines the hypothesis that alcohol consumption affects levels of reproductive hormones. Methods A controlled-diet study lasting for six consecutive menstrual cycles was conducted. Participants were randomly assigned to two groups, and a crossover design was used. During the last three menstrual cycles, alcohol consumption of the two groups was reversed. Thirty-four premenopausal women, aged 21-40 years, with a history of regular menstrual cycles, consumed 30 g of ethanol (equivalent to approximately two average drinks) per day for three menstrual cycles and no alcohol for the other three. All food and alcohol consumed were provided by the study. Caloric intake was monitored to ensure that each woman would maintain body weight at approximately the baseline level. Hormone assays were performed on pooled plasma or 24-hour urine specimens collected during the follicular (days 5-7), peri-ovulatory (days 12-15), and mid-luteal (days 21-23) phases of the third menstrual cycle for subjects on each diet. Results Alcohol consumption was associated with statistically significant increases in levels of several hormones. Plasma dehydroepiandrosterone sulfate levels were 7.0% higher in the follicular phase (P = .05). In the peri-ovulatory phase, there were increases of 21.2% (P = .01) in plasma estrone levels, 27.5% (P = .01) in plasma estradiol levels, and 31.9% (P = .009) in urinary estradiol levels. In the luteal phase, urinary estrone levels rose 15.2% (P = .05), estradiol levels increased 21.6% (P = .02), and estriol levels rose 29.1% (P = .03). No changes were found in the percent of bioavailable estradiol, defined by the sum of percent free estradiol and percent albumin-bound estradiol. However, increased total estradiol levels in the peri-ovulatory phase suggest elevated absolute amounts of bioavailable estradiol. Conclusion This study has shown increases in total estrogen levels and amount of bioavailable estrogens in association with alcohol consumption in premenopausal women. Implication This possible explanatory mechanism for a positive association between alcohol consumption and breast cancer risk merits further investigation.

Journal ArticleDOI
TL;DR: There were PT-induced reductions in parenting stress and increases in parenting self-esteem, which accompanied parent-reported improvements in the overall severity of their child's ADHD symptoms.
Abstract: This study examined changes in parent functioning resulting from parental participation in a behavioral parent training (PT) program specifically designed for school-aged children with attention-deficit hyperactivity disorder (ADHD). Relative to wait list controls, subjects who completed the nine-session PT program showed significant posttreatment gains in both child and parent functioning, which were maintained 2 months after treatment. In particular, there were PT-induced reductions in parenting stress and increases in parenting self-esteem, which accompanied parent-reported improvements in the overall severity of their child's ADHD symptoms. In addition to their statistical importance, these findings are discussed in terms of their clinical significance, utilizing methods developed by Jacobson and Truax (1991).