Showing papers by "University of Texas at Dallas published in 1999"

Country-Specific Factors Related to Financial Reporting and the Value Relevance of Accounting Data

Abstract: Using financial accounting data from manufacturing firms in 16 countries for 1986-1995, we demonstrate that the value relevance of financial reports is lower for countries where the financial systems are bank-oriented rather than market-oriented; where private sector bodies are not involved in standard setting process; where accounting practices follow the Continental model as opposed to the British-American model; where tax rules have a greater influence on financial accounting measurements; and where spending on auditing services is relatively low. Results are robust to alternative measures of value relevance of financial accounting data, including measures based on earnings (using a regression and a hedge-portfolio approach), accruals, and earnings and book value of equity combined. We show that the extent to which earnings information is reflected in leading-period returns as compared to contemporaneous returns is greater for bank-oriented than for market-oriented countries. This feature potentially induces spurious associations between value relevance measures and financial system characteristics. Our results are robust to using value relevance measures adjusted for this confounding effect.

From object-oriented to goal-oriented requirements analysis

Abstract: were proposed more than 10 years ago. The Object-Oriented Systems Analysis (OOSA) technique [12] adopts the Entity-Relationship (ER) model to capture the declarative aspects of a software system. This was soon followed by two new proposals, Object-Oriented Analysis [3] and the Object-Oriented Modeling Technique (OMT) [11], which support the modeling of declarative, behavioral as well as interactive aspects of a software system. Today, there are dozens of like-minded techniques and commercial tools founded on the OO way of thinking that support development from requirements analysis to implementation. Indeed, the great promise of OOA is that the whole software development process can be streamlined and simplified by having the same building blocks (objects, classes, methods, messages, inheritance and the like) used in all phases of development, from requirements to implementation. A recent proposal, the Unified Modeling Language (UML)—see www.rational. com/uml—attempts to integrate features of the more preeminent models in OOA, thereby enhancing reusability and consolidating the growing OOA market. Why is OOA popular? In a nutshell, because it significantly advances the state of practice in requirements modeling. The pracThe growing influence of object-oriented programming on programming practice

Sense of Community and Neighbourhood Form: An Assessment of the Social Doctrine of New Urbanism:

Abstract: New urbanism, an umbrella term which encompasses 'neotraditional development' as well as 'traditional neighbourhood design', lives by an unswerving belief in the ability of the built environment to...

Hypertriglyceridemia, insulin resistance, and the metabolic syndrome.

Abstract: The metabolic syndrome consists of a cluster of metabolic disorders, many of which promote the development of atherosclerosis and increase the risk of cardiovascular disease events. Insulin resistance may lie at the heart of the metabolic syndrome. Elevated serum triglycerides commonly associate with insulin resistance and represent a valuable clinical marker of the metabolic syndrome. Abdominal obesity is a clinical marker for insulin resistance. The metabolic syndrome manifests 4 categories of abnormality: atherogenic dyslipidemia (elevated triglycerides, increased small low-density lipoproteins, and decreased high-density lipoproteins), increased blood pressure, elevated plasma glucose, and a prothrombotic state. Various therapeutic approaches for the patient with the metabolic syndrome should be implemented to decrease the risk of cardiovascular disease events. These interventions include decreasing obesity, increasing physical activity, and managing dyslipidemia; the latter may require the use of pharmacotherapy with cholesterol-lowering and triglyceride-lowering drugs.

Functional requirement of p23 and Hsp90 in telomerase complexes

Abstract: Most normal human diploid cells have no detectable telomerase; however, expression of the catalytic subunit of telomerase is sufficient to induce telomerase activity and, in many cases, will bypass normal senescence. We and others have previously demonstrated in vitro assembly of active telomerase by combining the purified RNA component with the reverse transcriptase catalytic component synthesized in rabbit reticulocyte extract. Here we show that assembly of active telomerase from in vitro-synthesized components requires the contribution of proteins present in reticulocyte extracts. We have identified the molecular chaperones p23 and Hsp90 as proteins that bind to the catalytic subunit of telomerase. Blockade of this interaction inhibits assembly of active telomerase in vitro. Also, a significant fraction of active telomerase from cell extracts is associated with p23 and Hsp90. Consistent with in vitro results, inhibition of Hsp90 function in cells blocks assembly of active telomerase. To our knowledge, p23 and Hsp90 are the first telomerase-associated proteins demonstrated to contribute to telomerase activity.

Intensive high-dose asparaginase consolidation improves survival for pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma: a Pediatric Oncology Group study.

Abstract: This study was designed to test the hypothesis that high-dose asparaginase consolidation therapy improves survival in pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma. Five hundred and fifty-two patients (357 patients with T cell acute lymphoblastic leukemia (ALL) and 195 patients with advanced stage lymphoblastic lymphoma) were enrolled in POG study 8704 (T-3). Treatment included rotating combinations of high-dose myelosuppressive chemotherapy agents proven to be effective in T cell ALL in other POG group-wide or local institutional protocols (including vincristine, doxorubicin, cyclophosphamide, prednisone, asparaginase, teniposide, cytarabine and mercaptopurine). After achieving a complete remission (CR), patients were randomized to receive or not receive high-dose intensive asparaginase consolidation (25,000 IU/m2) given weekly for 20 weeks by intramuscular injection. Intrathecal chemotherapy (methotrexate, hydrocortisone and cytarabine) was given to prevent CNS disease, and CNS irradiation was used only for patients with leukemia and an initial WBC of >50,000/microl or patients with active CNS disease at diagnosis. CR was achieved in 96% of patients. The high-dose asparaginase regimen was significantly superior to the control regimen for both the leukemia and lymphoma subgroups. Four-year continuous complete remission rate (CCR) for the leukemia patients was 68% (s.e. 4%) with asparaginase as compared to 55% (s.e. 4%) without. For the lymphoma patients, 4-year CCR was 78% (s.e. 5%) with asparaginase and 64% (s.e. 6%) in the controls. The overall one-sided logrank test had a P value <0.001 favoring asparaginase, while corresponding values were P = 0.002 for ALL and P = 0.048 lymphoblastic lymphoma. Toxicities were tolerable, but there were 18 failures due to secondary malignancies (16 with non-lymphocytic leukemia or myelodysplasia). Neither WBC at diagnosis (leukemia patients) nor lymphoma stage were major prognostic factors. We conclude that when added to a backbone of effective rotating agents, repeated doses of asparaginase during early treatment improve the outcome for patients with T cell leukemia and advanced stage lymphoblastic lymphoma.

Sequential molecular abnormalities are involved in the multistage development of squamous cell lung carcinoma

Abstract: To understand the molecular pathways involved in the pathogenesis of squamous cell lung carcinoma, we obtained DNA from 94 microdissected foci from 12 archival surgically resected tumors including histologically normal epithelium (n=13), preneoplastic lesions (n=54), carcinoma is situ (CIS) (n=15) and invasive tumors (n=12). We determined loss of heterozygosity (LOH) at 10 chromosomal regions (3p12, 3p14.2, 3p14.1-21.3, 3p21, 3p22-24, 3p25, 5q22, 9p21, 13q14 RB, and 17p13 TP53) frequently deleted in lung cancer, using 31 polymorphic microsatellite markers, including 24 that spanned the entire 3p arm. Our major findings are as follows: (1) Thirty one percent of histologically normal epithelium and 42% of mildly abnormal (hyperplasia/metaplasia) specimens had clones of cells with allelic loss at one or more regions; (2) There was a progressive increase of the overall LOH frequency within clones with increasing severity of histopathological changes; (3) The earliest and most frequent regions of allelic loss occurred at 3p21, 3p22-24, 3p25 and 9p21; (4) The size of the 3p deletions increased with progressive histologic changes; (5) TP53 allelic loss was present in many histologically advanced lesions (dysplasia and CIS); (6) Analyses of 58 normal and non-invasive foci having any molecular abnormality, indicated that 30 probably arose as independent clonal events, while 28 were potentially of the same clonal origin as the corresponding tumor; (7) Nevertheless, when the allelic losses in the 30 clonally independent lesions and their clonally unrelated tumors were compared the same parental allele was lost in 113 of 125 (90%) of comparisons. The mechanism by which this phenomenon (known as allele specific mutations) occurs is unknown; (8) Four patterns of allelic loss in clones were found. Histologically normal or mildly abnormal foci had a negative pattern (no allelic loss) or early pattern of loss while all foci of CIS and invasive tumor had an advanced pattern. However dysplasias demonstrated the entire spectrum of allelic loss patterns, and were the only histologic category having the intermediate pattern. Our findings indicate that multiple, sequentially occurring allele specific molecular changes commence in widely dispersed, apparently clonally independent foci, early in the multistage pathogenesis of squamous cell carcinomas of the lung.

The cognitive interview: A meta-analysis

Abstract: A meta-analysis was performed on the effects of the cognitive interview on correct and incorrect recall. The database comprised 42 studies with 55 individual comparisons involving nearly 2500 interviewees. A strong overall effect size was found for the increase of correctly recalled details with the cognitive interview compared to a control interview (d = 0.87). The overall effect size for the increase in incorrect details, although considerably smaller, was also significant toward the cognitive interview (d = 0.28). However, the accuracy rates (proportion of correct details relative to the total amount of details reported) were almost identical in both types of interview (85% for the cognitive interview and 82% for standard interviews, respectively). Taking methodological factors into consideration it was found that effect sizes for correct details were larger if staged events were used as the to-be-remembered episode (as compared to video films) and if the interviewees actively participated in ...

Teletraffic analysis and mobility modeling of PCS networks

Abstract: Channel holding time is of primary importance in teletraffic analysis of PCS networks. This quantity depends on user's mobility which can be characterized by the cell residence time. We show that when the cell residence time is not exponentially distributed, the channel holding time is not exponentially distributed either, a fact also confirmed by available field data. In order to capture the essence of PCS network behaviour, including the characterization of channel holding time, a correct mobility model is therefore necessary. The new model must be good enough to fit field data, while at the same time resulting in a tractable queueing system. We propose a new mobility model, called the hyper-Erlang distribution model, which is consistent with these requirements. Under the new realistic operational assumption of this model, in which the cell residence time is generally distributed, we derive analytical results for the channel holding time distribution, which are readily applicable to the hyper-Erlang distribution models. Using the derived analytical results we demonstrate how the distribution of the cell residence time affects the channel holding time distribution. The results presented in this paper can provide guidelines for field data processing in PCS network design and performance evaluation.

Nerve growth factor induces survival and differentiation through two distinct signaling cascades in PC12 cells

Abstract: Nerve growth factor induces differentiation and survival of rat PC12 pheochromocytoma cells. The activation of the erk cascade has been implicated in transducing the multitude of signals induced by NGF. In order to explore the role of this signaling cascade in NGF mediated survival, differentiation and proliferation, we generated recombinant adenoviruses which express the intermediates of the erk cascade in their wild type, dominant negative and constitutively activated forms. We show that differentiation of PC12 cells requires activity of the ras/erk pathway, whereas inhibition of this pathway had no effect on survival or proliferation. Constitutively active forms of ras, raf and mek induced PC12 cell differentiation, while dominant interfering forms inhibited differentiation. Survival of PC12 cells in serum-free medium did not require activity of the ras/erk pathway. Instead, PI3 Kinase signaling was necessary for PC12 cell survival. Interestingly, constitutively activated versions of raf and mek were able to promote survival, but again this was dependent on activation of PI3 Kinase. Therefore, at least two distinct signaling pathways are required in PC12 cells for mediation of NGF functions.

Morphological productivity in children with normal language and SLI: a study of the English past tense.

Abstract: Children with specific language impairment (SLI) are known to display persistent difficulties with inflectional morphology—in particular, the overuse of unmarked grammatical forms (i.e., zero-marking). Yet, several recent studies have shown that English-speaking children with SLI, like their normal language peers (NL), demonstrate a considerable degree of productive language abilities (e.g., Bishop, 1994; Loeb & Leonard, 1991; Oetting & Horohov, 1997). In this study, we explore productivity in the English past tense in school-age children with SLI (N=31) and NL (N=31) who were equivalent as a group in chronological and mental age. Although children in both groups produced a range of error types, the children with SLI produced significantly more errors, with a greater proportion resulting from zero-marking (e.g., go) than suffixation (e.g., goed). Item analyses indicated that suffixations and zero-markings were predicted by item frequency, phonological features of stems, and similarity relationships across...

Optimal Pricing Strategy for New Products

Abstract: Robinson and Lakhani (1975) initiated a long research stream in marketing when they used the Bass model (1969) to develop optimal pricing path for a new product. A careful analysis of the extant literature reveals that the research predominantly suggests that the optimal price path should be largely based on the sales growth pattern. However, in the real world we rarely find new products that have such pricing pattern. We observe either a monotonically declining pricing pattern or an increase-decrease pricing pattern that does not seem close to the sales path. In this paper, we use a variation of the generalized Bass model (called GBM) developed by Bass et al. (1994) that yields optimal pricing policies that are consistent with empirical data.

On the number of channels needed to understand speech

Abstract: Recent studies have shown that high levels of speech understanding could be achieved when the speech spectrum was divided into four channels and then reconstructed as a sum of four noise bands or sine waves with frequencies equal to the center frequencies of the channels. In these studies speech understanding was assessed using sentences produced by a single male talker. The aim of experiment 1 was to assess the number of channels necessary for a high level of speech understanding when sentences were produced by multiple talkers. In experiment 1, sentences produced by 135 different talkers were processed through n (2⩽n⩽16) number of channels, synthesized as a sum of n sine waves with frequencies equal to the center frequencies of the filters, and presented to normal-hearing listeners for identification. A minimum of five channels was needed to achieve a high level (90%) of speech understanding. Asymptotic performance was achieved with eight channels, at least for the speech material used in this study. The outcome of experiment 1 demonstrated that the number of channels needed to reach asymptotic performance varies as a function of the recognition task and/or need for listeners to attend to fine phonetic detail. In experiment 2, sentences were processed through 6 and 16 channels and quantized into a small number of steps. The purpose of this experiment was to investigate whether listeners use across-channel differences in amplitude to code frequency information, particularly when speech is processed through a small number of channels. For sentences processed through six channels there was a significant reduction in speech understanding when the spectral amplitudes were quantized into a small number (<8) of steps. High levels (92%) of speech understanding were maintained for sentences processed through 16 channels and quantized into only 2 steps. The findings of experiment 2 suggest an inverse relationship between the importance of spectral amplitude resolution (number of steps) and spectral resolution (number of channels).

Impact of information quality and decision-maker quality on decision quality: a theoretical model and simulation analysis

Abstract: The impact of information technology (IT) on firm performance is widely studied but little understood. A common perception is that IT improves the quality of information, which, in turn, improves decision quality and performance. Several studies of IT-performance relationship have used managers' perceived as opposed to actual performance. We investigate the impact of information quality and decision-maker quality on actual decision quality using a theoretical and a simulation model. We use accuracy as the measure of quality. Our analysis shows that, depending on the decision-maker quality, decision quality may improve or degrade when information quality improves. The decision quality improves with higher information quality for a decision-maker that has knowledge about the relationships among problem variables. However, the decision quality of a decision-maker that doesn't know these relationships may degrade with higher information quality. Simultaneous improvement in information quality and decision-maker quality results in higher decision quality. The simulation model, which relaxes some of the assumptions made by the theoretical model, yields similar results. We explain how our results supplement the results of prior studies of IT-performance relationship. Our results underscore the need for including decision-maker quality in the investigation of the IT-performance relationship and the importance of developing quality decision support tools.

Transforming growth factor(beta)-mediated corneal myofibroblast differentiation requires actin and fibronectin assembly.

Abstract: PURPOSE Recent studies indicate that transforming growth factor (TGF)beta is a potent inducer of corneal myofibroblast differentiation and expression of smooth muscle-specific, alpha-actin (alpha-SMA). Although TGFbeta is known to enhance synthesis of extracellular matrix proteins and receptors, little is known about how it modulates the expression of smooth muscle proteins in nonmuscle cells. The purpose of this study was to identify the role of Arg-Gly-Asp (RGD)-dependent tyrosine phosphorylation in regulating alpha-SMA gene expression and ultimately myofibroblast development. METHODS Because cell culture in serum-containing media mimics myofibroblast transformation, all experiments were performed on freshly isolated rabbit keratocytes plated in defined, serum-free media. Cells were exposed to TGFbeta (1 ng/ml), Gly-Arg-Gly-Asp-D-Ser-Pro (GRGDdSP, 50 microM), Gly-Arg-AL-Asp-Ser-Pro (GRADSP; 100 microM), or herbimycin A (0.1-10 nM) at 24 hours (sparse) or 7 days (confluent). Cells were evaluated by immunocytochemistry and proteins and RNA collected for western and northern blot analyses using antibodies specific for alpha-SMA, fibronectin, focal adhesion proteins, and phosphotyrosine (clones 4G10 and PY20); and probes directed against rabbit alpha-SMA. All experiments were repeated at least three times. RESULTS Keratocytes exposed to TGFbeta showed expression of alpha-SMA that coincided with the intracellular reorganization of the actin cytoskeleton and the extracellular assembly of fibronectin fibrils. Addition of RGD containing but not control peptides blocked the organization of intracellular actin, extracellular fibronectin, and alpha-SMA protein and mRNA. Immunoprecipitation of cell proteins with 4G10 or PY20 identified the TGFbeta-associated tyrosine phosphorylation of paxillin, pp125fak, p130, PLCgamma, and tensin, which was blocked by addition of GRGDdSP. Addition of herbimycin A to keratocytes exposed to TGFbeta showed a dose-dependent loss of alpha-SMA protein and mRNA which correlated with loss of tyrosine phosphorylation, absence of actin reorganization, and fibronectin assembly. CONCLUSIONS The data suggest that TGFbeta-mediated alpha-SMA gene expression leading to myofibroblast transformation may involve an RGD-dependent phosphotyrosine signal transduction pathway.

A Study of Factors Influencing the Growth of Nonprofits in Social Services

Abstract: This exploratory study identifies and assesses the significance of factors that contribute to the growth of the nonprofit sector in the field of social services across 285 major metropolitan areas in the United States. Measures derived from social cohesion, demand heterogeneity, market failure, resource dependence, and philanthropic culture theories are introduced to correlation and multiple regression analyses. All but the philanthropic culture measures are positively associated with the growth of the nonprofit sector in social services. Particularly noteworthy are the positive influences that religious cohesion and interdenominational diversity have on numbers of nonprofit social service providers—a finding that reaffirms the historical linkage between religion and voluntary associations. Summary U.S. economic and sociodemographic census data, as well as data from a unique religious census, are analyzed. If a unifying theory of the nonprofit sector is attainable, studies such as this should contribute to laying the empirical building blocks for such a theory.

Information dissemination in partitionable mobile ad hoc networks

Abstract: Ad-hoc wireless networks have no wired component, and may have unpredictable mobility pattern. Such networks can get partitioned and reconnected several times. One possible approach for information dissemination in such networks is to replicate information at multiple nodes acting as repositories, and employ quorum based strategies to update and query information. We propose three such strategies that also use local knowledge about the reachability of repositories to judiciously select quorums. The primary goal is high availability of information in the face of network partitioning. We also consider four policies to determine the appropriate time to perform updates. Experimental results indicate that a hybrid information management strategy and an absolute connectivity-based update trigger policy are most suited for partitionable ad-hoc networks.

Comparison of features of human breast cancer cell lines and their corresponding tumors.

Abstract: Although human tumor-derived cell lines play an important role in the investigation of cancer biology and genetics, there is no comprehensive study comparing tumor cell line properties with those of the individual tumors from which they were derived. We compared the properties of a series of 18 human breast cancer cell lines that were cultured for a median period of 25 months (range, 9-60 months) and their corresponding archival tumor tissues. We compared morphological characteristics, ploidy, and immunohistochemical expression of estrogen receptors, progesterone receptors, and HER2/neu and p53 proteins. For 17 of these cases, we also tested for allelic losses at 18 chromosomal regions frequently deleted in breast tumors using 51 polymorphic microsatellite markers, and we determined the TP53 gene mutation status in exons 5 to 10. There was an excellent correlation between the breast tumor cell lines and their corresponding tumor tissues for morphological features (100%); presence of aneuploidy (87%); immunohistochemical expression of estrogen receptors (87%), progesterone receptors (73%), and HER2/neu (93%) and p53 proteins (100%); allelic loss at all of the chromosomal regions analyzed (82-100% concordance); and TP53 gene mutations (75%). The same parental allele was lost in 279 (99%) of 281 of the comparisons of allelic losses. The fractional allelic loss indices (a reflection of the total allelic loss) of the cell lines and their corresponding tumor tissues were identical or similar in 15 (88%) of 17 paired comparisons. Although our previous studies (A. Gazdar et al., Int. J. Cancer, in press) indicated that only a subset of primary breast carcinomas that have several features indicative of advanced tumors with poor prognosis can be successfully cultured, the cell lines retain the properties of their parental tumors for lengthy culture periods and, thus, provide suitable model systems for biomedical studies.

Age differences in accuracy and choosing in eyewitness identification and face recognition.

Abstract: Studies of aging and face recognition show age-related increases in false recognitions of new faces. To explore implications of this false alarm effect, we had young and senior adults perform (1) three eyewitness identification tasks, using both target present and target absent lineups, and (2) an old/new recognition task in which a study list of faces was followed by a test including old and new faces, along with conjunctions of old faces. Compared with the young, seniors had lower accuracy and higher choosing rates on the lineups, and they also falsely recognized more new faces on the recognition test. However, after screening for perceptual processing deficits, there was no age difference in false recognition of conjunctions, or in discriminating old faces from conjunctions. We conclude that the false alarm effect generalizes to lineup identification, but does not extend to conjunction faces. The findings are consistent with age-related deficits in recollection of context and relative age invariance in perceptual integrative processes underlying the experience of familiarity.

Unidirectional links prove costly in wireless ad hoc networks

Abstract: Most, of t,he routing algorithms for ad hoc net,works assume t,hat all wireless links are bidirect,ional. In realit,y, some links may be unidirect.ional. The presence of such links can jeopardize t,he performance of t,he existing dist,ance vect.or rout.ing algorit.hms. In this paper we show t,hat, dist.ance vector based rout,ing prot.ocols t,hat, account for unidirectional links will require nodes t.o exchange O(n2) informat.ion with each other, where n is t.he number of nodes in t,he nebwork. We also present. modifications to dist,ance vector based routing algorithms to make t,hem work in ad hoc netsworks wit.h unidirectional links.

Consistent time-of-flight mobility measurements and polymer light-emitting diode current–voltage characteristics

Abstract: We present time-of-flight mobility measurements and measured and calculated current–voltage (I–V) characteristics of structures fabricated using a soluble poly(p-phenylene vinylene) derivative. Time-of-flight measurements were used to determine the electric field dependent hole mobility. This mobility was then used, without adjustable parameters, to calculate the I–V characteristics of space-charge-limited, hole only devices. The measured and calculated I–V characteristics are in good agreement over five orders of magnitude in current. These results demonstrate that an electric field dependent mobility, without invoking trapping effects, provides an accurate description of hole transport in this polymer.

Secrets of success: assessing the large increases in transit ridership achieved by Houston and San Diego transit providers

Abstract: This paper summarizes and updates the findings from an earlier study by the same authors of transit systems in Houston (all bus) and San Diego (bus and light rail). Both systems achieved unusually large increases in transit ridership during a period in which most transit systems in other metropolitan areas were experiencing large losses. Based on ridership models estimated using cross section and time series data, the paper quantifies the relative contributions of policy variables and factors beyond the control of transit operators on ridership growth. It is found that large ridership increases in both areas are caused principally by large service increases and fare reductions, as well as metropolitan employment and population growth. In addition, the paper provides careful estimates of total and operating costs per passenger boarding and per passenger mile for Houston's bus operator and San Diego's bus and light rail operators. These estimates suggest that the bus systems are more cost-effective than the light rail system on the basis of total costs. Finally, the paper carries out a series of policy simulations to analyze the effects of transit funding levels and metropolitan development patterns on transit ridership and farebox recovery ratio.

Brachial amyotrophic diplegia: a slowly progressive motor neuron disorder.

Abstract: Objective: To describe a sporadic motor neuron disorder that remains largely restricted to the upper limbs over time. Background: Progressive amyotrophy that is isolated to the upper limbs in an adult often suggests ALS. The fact that weakness can remain largely confined to the arms for long periods of time in individuals presenting with this phenotype has not been emphasized. Methods: We reviewed the records of patients who had a neurogenic “man-in-the-barrel” phenotype documented by examination at least 18 months after onset. These patients had severe bilateral upper-extremity neurogenic atrophy that spared lower-extremity, respiratory, and bulbar musculature. Results: Nine of 10 patients meeting these criteria had a purely lower motor neuron disorder. During follow-up periods ranging from 3 to 11 years from onset, only three patients developed lower-extremity weakness, and none developed respiratory or bulbar dysfunction or lost the ability to ambulate. Conclusion: Patients presenting with severe weakness that is fully isolated to the upper limbs, without pyramidal signs, may have a relatively stable variant of motor neuron disease.

A new approach to the design and analysis of peer-to-peer mobile networks

Abstract: This paper introduces a new model and methodological approach for dealing with the probabilistic nature of mobile networks based on the theory of random graphs. Probabilistic dependence between the random links prevents the direct application of the theory of random graphs to communication networks. The new model, termed Random Network Model, generalizes conventional random graph models to allow for the inclusion of link dependencies in a mobile network. The new Random Network Model is obtained through the superposition of Kolmogorov complexity and random graph theory, making in this way random graph theory applicable to mobile networks. To the best of the authors' knowledge, it is the first application of random graphs to the field of mobile networks and a first general modeling framework for dealing with ad-hoc network mobility. The application of this methodology makes it possible to derive results with proven properties. The theory is demonstrated by addressing the issue of the establishment of a connected virtual backbone among mobile clusterheads in a peer-to-peer mobile wireless network. Using the Random Network Model, we show that it is possible to construct a randomized distributed algorithm which provides connectivity with high probability, requiring exponentially fewer connections (peer-to-peer logical links) per clusterhead than the number of connections needed for an algorithm with a worst case deterministic guarantee.

Identification and function of neonatal Fc receptor in mammary gland of lactating mice.

Abstract: In addition to its proposed function in regulating serum IgG levels, the MHC class I-related neonatal Fc receptor (FcRn) is known to play a role in IgG transfer across rodent yolk sac and neonatal intestine. In contrast to humans, for which transplacental transfer of IgG appears to be the only mechanism of maternal IgG delivery, the transmission of IgG in mice occurs both antenatally (yolk sac) and neonatally (transport from mother's milk across intestinal epithelial cells). In the current study, a possible role for FcRn in regulating IgG transfer into milk has been investigated. FcRn has been shown to be present in functional form in the mammary gland of lactating mice, and is localized to the epithelial cells of the acini. Analysis of the transfer of Fc fragments and IgG which have different affinities for FcRn indicate that, unexpectedly, these proteins are transferred in inverse correlation with their binding affinity for FcRn. Thus, in the lactating mammary gland FcRn appears to play a role in recycling IgG in a mode that may have relevance to FcRn trafficking during the maintenance of constant serum IgG levels.

A Note on the Correspondence Between Complexity and Systems Theory

Abstract: Complexity theory shares a common vocabulary with systems theory. Terms such as emergence, complexity, and adaptation appear in both traditions. Despite the similarities, complexity theory is not a misnomer for systems theory. Several points of departure exist in complexity's research agenda and methods. Moreover, while systems theory appears to have embraced interpretivist and critical philosophies, complexity theory remains firmly in the positivist camp, despite claims that it is a postmodern science.

Interorganizational Collaborative Forecasting and Replenishment Systems and Supply Chain Implications

Abstract: Collaborative Forecasting and Replenishment (CFAR) is a new interorganizational system that enables retailers and manufacturers to forecast demand and schedule production jointly. The capabilities of CFAR exceed those of the traditional EDI because CFAR allows exchange of complex decision support models and manufacturer/retailer strategies. The proponents of CFAR claim that the fastest way for retailers and manufacturers to slash inventory costs and product shortages is by coordinating their decisions. The impact of CFAR on the supply chain using a model consisting of a manufacturer selling its product through two independent identical retailers is analyzed. The model assumes that the manufacturer doesn't face capacity constraints, the demand is stationary, and retailer prices are constant over time; the shortages are backordered at the manufacturer and retailers to isolate the effects of information sharing in CFAR. The most significant findings relate to the increase in the cost incurred by the nonparticipant in CFAR, the increase in the manufacturer's cost of serving the nonparticipant if the participant can obtain delivery guarantees in return for demand information sharing, and the incentives of the players to move towards universal retailer participation in CFAR. The findings are explained using the risk structure faced by the players in the supply chain. The managerial implications of the impact of CFAR on the supply chain structure are also discussed.