cssi/SciSciGPT-SciSciNet huggingface dataset:
When Do Children Lose the Language Instinct? A Critical Review of the Critical Periods Literature

While it is clear that children are more successful at learning language than adults are—whether first language or second—there is no agreement as to why. Is it due to greater neural plasticity, gr...
Empathy, Intersubjectivity, and the Self

The idea of empathy illuminates a fundamental aspect of our lives: the fact that our social world is intersubjective, that what we think and feel is connected to what others think and feel. This chapter traces the development of this concept from its classical sociological roots to the present moment. The first part of the chapter concentrates on Charles Cooley’s (1864–1929) classical theory, which contains a multifaceted conceptualization of empathy with striking resemblances to contemporary sociological understandings. After discussing Cooley’s view of the socialization of feeling, it presents an interpretive reconstruction of three conceptual facets of empathy: imaginative, interactional, and purposive. This conceptualization offers us the tools to theorize empathy in three distinct ways: as a means for knowing; as a means for intersubjective understanding; and as a means for exerting power. Next, the chapter discusses the evolution of the empathy concept after the classical period. With its formal introduction in the sociological vocabulary, this idea changes meanings in subsequent decades. The chapter ends with a consideration of current scholarly understandings.
Four Components of Expertise

This paper aims to extend the concept of expertise, with a focus on its application to polymathy studies and to the three elements of polymathy: depth, breadth and integration. Departing from Herling’s (2000) "Operational definitions of expertise and competence", in which he outlines three basic components of expertise (knowledge, problem-solving, and experience), I propose a more sophisticated differentiation that involves four types of knowledge: (1) Epistemic Knowledge; (2) Tooled Knowledge; (3) Idiosyncratic Knowledge; and (4) Meta-Knowledge.
We're Not in Dreamland Anymore: How Regional Opioid Use Rates Affect Industrial Composition

The opioid crisis has adversely affected nearly every aspect of life in some U.S. communities. Understanding how regional opioid use rates affect firm resources, and thus the industrial landscape, is vital to understanding long-term economic and fiscal effects. In this study, I estimate the causal effect of regional opioid use rates on firm resources, and industrial composition by using high-volume opioid dispensing pharmacies (pill mills) as an instrument. I find regional opioid use rates adversely affect firms in general, with differential effects across firm size, and industry. I also find adverse impacts on labor supply, and consider long-term economic and fiscal implications. Together, these findings link public health to long-term economic vitality and fiscal capacity.
Who Am I? The Social Construction of Ethnic Identity and Self-Perceptions in Latino Preservice Teachers

Because of the changes in the demographics, it is important for Latino teachers to relate to the educational and psychological needs of language minority children who are predominately Latino. For teacher educators, the question is whether teacher preparation should include the development and enhancement of a positive self-image in teachers and should provide teachers with the techniques necessary to promote a positive ethnic identity in their students. A preliminary study was conducted focusing on Latino teachers' ethnicity labels and self-conceptualizations. The questions addressed are: How do bilingual teachers identify themselves ethnically, and what are their self-conceptualizations? And is there a within-group difference in how these Latino teachers identify themselves? The findings show that there is a strong association between ethnic identity and self-concept and that there are group differences.
Three-dimensional object recognition using laser radar

Short-pulse laser radar systems are capable of producing range-resolved, i.e., three-dimensional (3-D), images which can be used for automatic object detection and recognition. The success achieved in these scene understanding tasks relies in part on the development of effective image processing algorithms. In the practical realm, algorithm design is governed by trade-offs among detection or recognition performance and speed, implementation ease and cost, and other factors. This thesis addresses the need for a theoretical approach to algorithm design. A central objective of this thesis is to develop detection and recognition processors which can serve as benchmarks for processors subject to a broad range of design constraints. A Neyman-Pearson criterion for statistical optimality is adopted, leading to statistically optimal likelihood ratio test (LRT) detectors and recognizers. Generalized LRT processors result when unknown parameters are considered. In a departure from previous work, unknown range profiles are considered. Consequently, a general theory for maximum-likelihood (ML) range-profiling is derived, and is implemented using the expectation-maximization (EM) algorithm for the case of planar range-profiling. Performance predictions for the collection of estimation, detection and recognition algorithms derived herein are made via computer simulation. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)
Maximum discharge from snowmelt in a changing climate

[1] Predicted changes in precipitation and air temperature patterns can lead to major alterations in timing and volume of mountain snowmelt runoff with a possible increased incidence of catastrophic events such as flooding and summer droughts. Here, the role of the temperature seasonal cycle and the relative duration of cold and warm seasons on the partitioning of precipitation into snow and rainfall, snow accumulation and melting dynamics, and the resulting mountain runoff formation are investigated. Using a minimalist analytical model, it is shown that while increased air temperatures reduce snow accumulation in the winter, thus reducing the subsequent snowmelt volumes, they also intensify the rate of snowmelt, thus increasing the discharge peaks per given accumulated snow. The main consequence is the existence of an optimal energy input for which the annual peak discharge reaches an absolute maximum. Such maximum separates a cold regime, where peak discharge is limited by slow melting dynamics, from a warm regime in which peak discharge is reduced by decreased winter snow accumulation.
Tensor Components of Infinitesimal Strain, II

In the last chapter it was claimed that $$ \left[ \begin{gathered} {e_{{11}}}\quad {e_{{12\quad }}}{e_{{13}}} \hfill \\ {e_{{21}}}\quad {e_{{22}}}\quad {e_{{23}}} \hfill \\ {e_{{31}}}\quad {e_{{32}}}\quad {e_{{33}}} \hfill \\ \end{gathered} \right] = \left[ \begin{gathered} {\varepsilon_{{11}}}\quad \frac{1}{2}{\gamma_{{12}}}\quad \frac{1}{2}{\gamma_{{13}}} \hfill \\ \frac{1}{2}{\gamma_{{21}}}\quad {\varepsilon_{{22}}}\quad \frac{1}{2}{\gamma_{{23}}} \hfill \\ \frac{1}{2}{\gamma_{{31}}}\quad \frac{1}{2}{\gamma_{{32}}}\quad {\varepsilon_{{33}}} \hfill \\ \end{gathered} \right] $$ where the e ij were defined in terms of displacement gradients and the ∊ ij and γ ij are the elongations and shear strains of lines initially parallel to the coordinate axes. We now demonstrate why this is so, first for a normal component (e11) and then for a shear component (e31).
A process to reuse experiences via narratives among software project managers

Software project management is a complex process requiring extensive planning, effective decision-making, and proper monitoring throughout the course of a project. Unfortunately, software project managers rarely capture and reuse the knowledge gained during a project on subsequent projects. To enable the repetition of prior successes and avoidance of previous mistakes, I propose that software project managers can improve their management abilities by reusing their own and others' past experiences with written narratives. I use multiple methodologies---including literature review, grounded theory, design science research, and experimentation---to create a process for software project managers to reuse knowledge gained through experiences on software projects. In the literature review, I examine relevant research areas to inspire ideas on how to reuse knowledge via written narratives in software project management. Interviews with software project managers, analyzed using grounded theory, provide insight into the current challenges of reusing knowledge during a project. I leverage design science research methodology to develop a process of experience reuse that incorporates narratives and wikis to enable software project managers to share their experiences using written narratives. Experimentation evaluates whether the process developed using the design science research methodology improves the current knowledge reuse practices of software project managers.
36th Annual David W. Smith Workshop on Malformations and Morphogenesis: Abstracts of the 2015 annual meeting.

The 41st Annual David W. Smith Workshop on Malformation and Morphogenesis was scheduled to take place in Skamania, Washington, on September 11-16, 2020. Due to the COVID-19 pandemic and the associated recommendations to avoid travel and congregation in large groups, this meeting took place differently from its original plan. Rather than bringing trainees, clinicians and researchers with an interest in congenital malformations and their underlying morphogenesis together for several days in a workshop with submitted presentations and research lectures, this meeting took place virtually. A 1 day online meeting was organized in order to allow trainees to present their work. This Conference Report includes the highest scoring abstracts submitted by trainees and presented at the 2020 virtual David W. Smith Workshop.
Drotner, K., & Schrøder, K. C. (Eds.). (2013). Museum Communication and Social Media: The Connected Museum. New York, NY: Routledge. 216 pages. ISBN: 13-978-0-415-83318-9 (hbk), USD $125.00; ISBN: 13-978-0-203-50096-5 (eBook), USD $125.00.

Reviewed by Emily FryPeabody Essex Museum, Salem, Massachusetts, USAWith social media increasingly being used as the dominant tool for smudging the line between online authority and museum communic...
Fungible Weights in Multiple Regression

Every set of alternate weights (i.e., nonleast squares weights) in a multiple regression analysis with three or more predictors is associated with an infinite class of weights. All members of a given class can be deemed fungiblebecause they yield identical SSE (sum of squared errors) and R 2 values. Equations for generating fungible weights are reviewed and an example is given that illustrates how fungible weights can be profitably used to evaluate parameter sensitivity in multiple regression.
Dexamethasone induced preadipocyte recruitment and expression of CCAAT/enhancing binding protein α and peroxisome proliferator activated receptor-γ proteins in porcine stromal-vascular (S-V) cell cultures obtained before and after the onset of fetal adipogenesis

Abstract The present study examined the influence of dexamethasone (DEX) treatment on preadipocyte recruitment and expression of transcription factor proteins in adipose tissue stromal-vascular (S-V) cell cultures from 50 and 75 day old pig fetuses and young pigs. C/EBPα, C/EBPδ, and PPARγ immunoreactive cells had evenly reactive nuclei and unreactive nucleoli. DEX recruited many more preadipocytes in 75 day than in 50 day fetal S-V cultures. However, DEX did not increase the number of differentiated preadipocytes (lipid+, C/EBPα+) in 50 day S-V cultures and only slightly increased this number in 75 day fetal S-V cultures. In fetal cultures, extensive, precocious increases in C/EBPα expression (number of reactive cells) by day three were followed by extensive decreases in expression. However, PPARγ expression was not expressed precociously since preadipocyte lipid accretion and PPARγ immunoreactivity were strongly linked in fetal and pig S-V cultures. Nevertheless, all cells with lipid in fetal S-V cultures were C/EBPα and PPARγ reactive. DEX increases preadipocyte differentiation in pig S-V cultures and in this study DEX increased PPARγ expression to a much greater degree in pig than in fetal S-V cultures. These studies suggest that restricted adipogenesis in the pig fetus is attributable to limited DEX induced PPARγ expression.
Analytic solution of the susceptible-infective epidemic model with state-dependent contact rates and different intervention policies

We consider the susceptible-infective (SI) epidemiological model, a variant of the Kermack-McKendrick models, and let the contact rate be a function of the number of infectives, an indicator of disease spread during the course of the epidemic. We represent the resultant model as a continuous-time Markov chain. The result is a pure death (or birth) process with state-dependent rates, for which we find the probability distribution of the associated Markov chain by solving the Kolmogorov forward equations. This model is used to find the analytic solution of the SI model as well as the distribution of the epidemic duration. We use the maximum likelihood method to estimate contact rates based on observations of inter-infection time intervals. We compare the stochastic model to the corresponding deterministic models through a numerical experiment within a typical household. We also incorporate different intervention policies for vaccination, antiviral prophylaxis, isolation, and treatment considering both full and partial adherence to interventions among individuals.
Synthesis of novel single-walled carbon nanotube—magnesium nanoparticle composites by a solution reduction method

Abstract Single-walled carbon nanotubes (SWNTs) reinforced with uniform distribution of magnesium nanoparticles were synthesized by a solution reduction method using a Grignard reagent and lithium naphthalide. Magnesium nanoparticles were observed to be of an average size of 4.5±0.5 nm. Raman data indicated distinct diameter selectivity for larger-diameter metallic SWNTs of 2.21 nm and some degree of de-bundling of the nanotube bundles upon the incorporation of the magnesium nanoparticles.
Properties of Grain Boundaries in Gold-Doped Germanium

It has been found that grain boundaries produce a path of relatively low electrical resistance at temperatures below \ensuremath{\sim}100\ifmmode^\circ\else\textdegree\fi{}K in Ge whose bulk resistivity has been made greater than ${10}^{3}$ to ${10}^{5}$ ohm-cm by the addition of Au. A new permanent-magnet apparatus for measuring the Hall effect in semiconductors at low temperatures is described. The results of measurement of the Hall effect as a function of temperature in Ge samples containing grain boundaries of known orientation are given. A peak in the Hall coefficient observed in some samples is discussed in terms of a crude model. Preferential conduction along grain boundaries also occurs in high-resistivity Fe-doped Ge, but has not been observed in crystals containing coherent twin boundaries. A modification of Bardeen's theory of surface states is used in an attempt to account for the existence of the grain-boundary conduction phenomenon.
Concesiones Malinchistas: Teresa de la Parra’s Identification with Doña Marina

In the first of a series of three lectures delivered in 1930 in Bogota, Colombia, on the roles women played in the history of Latin America, Venezuelan writer Teresa de la Parra (Ana Teresa Parra Sanojo) set out to revise Dona Marina’s role in Cortes’s Conquest of Mexico. By deflating the epic elements of the official historiography, Parra downplays Cortes’s heroic exploits to re-present Dona Marina as an exemplary female historical figure. While rectifying Dona Marina's story in the historical accounts, Parra commits a glaring omission. She glosses over the Cholula episode which has tarnished Dona Marina’s participation in the Conquest with the stigma of betrayal in the eyes of postcolonial nationalists. In this essay, I argue that this omission is particularly revealing about Parra’s life and writing. Haunted by a sense of national disaffection, Parra uses her “revised” portrait of Dona Marina to rehabilitate her own image as a Venezuelan writer vis-a-vis a nation that she had “betrayed” and a Latin American public that she had abandoned when she left Venezuela for France in 1923.
Application of Different Nitrogen Levels to the Host Plant and Cannibalistic Behavior of Beet Armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

The effects of dietary nitrogen levels on cannibalistic behavior of a generalist herbivore, beet armyworm, Spodoptera exigua (Hubner), were evaluated by rearing larvae on sugarbeet foliage from plants fertilized with less than normal, normal, and more than normal levels of nitrogen, and allowing larvae to cannibalize beet armyworm pupae. There was a significant inverse correlation between foliar nitrogen content and percent cannibalism. Fecundity was significantly increased by cannibalistic behavior among female larvae. Larval compensation for poor-quality diet by increased cannibalism is suggested as a potentially important factor in herbivore population dynamics.
Faith and Service in Private Non-Sectarian Colleges

This article explores both the historical and contemporary relationships between faith and service at some of the nation’s “private, non-sectarian” colleges. It documents the shift from religious to community service concerns at several colleges that occupy an important niche in American higher education, including Harvard, Yale, Dartmouth, and Bates. It argues that Dartmouth is unusual among its peers in keeping faith and service together in one office, and that this union is both problematic and possibly fruitful.
Assessment of cysteine synthesis in very low–birth weight neonates using a [13C6]glucose tracer

Abstract Background/Purpose Cysteine is an amino acid necessary for the synthesis of all proteins, the antioxidant glutathione, and the neuromodulator taurine. Whether cysteine is an essential amino acid for premature neonates remains controversial. Using a [ 13 C 6 ]glucose precursor in very-low–birth weight (VLBW) premature neonates, we measured the 13 C content of cysteine in hepatically derived apolipoprotein (apo) B-100 and in the plasma to determine whether cysteine synthesis occurs and to relate minimum synthetic capacity to neonatal maturity. Methods Twelve VLBW premature neonates (birth weight, 907 ± 274 [SD] g; gestational age, 26.8 ± 2.4 weeks) were studied on day of life 7.8 ± 4.2 while on total parenteral nutrition (TPN) for 5.6 ± 4.5 days. A 4-hour intravenous infusion of [ 13 C 6 ]glucose was administered. Blood samples were obtained immediately before and at the end of the infusion. Isotopic enrichment of cysteine was determined by gas chromatography/mass spectrometry. Analysis of variance, Student's t test, and linear regression were used for comparisons. Results The 13 C isotope ratio of apo B-100–derived cysteine after the [ 13 C 6 ]glucose infusion was significantly higher than baseline (18.57 ± 0.38 [SEM] vs 17.54 ± 0.25 mol%, P 13 C isotope ratio of plasma cysteine was also significantly higher than baseline (17.36 ± 0.25 vs 16.91 ± 0.16 mol%, P 13 C]apo B-100 cysteine/[ 13 C 6 ]glucose correlated with birth weight ( r = 0.74, P Conclusions Very low–birth weight neonates are capable of cysteine synthesis as evidenced by incorporation of 13 C label into hepatically derived apo B-100 cysteine and plasma cysteine from a glucose precursor. The minimum capacity for intrahepatic cysteine synthesis appears to be directly proportional to the maturity of the neonate and may impact the capabilities of VLBW neonates to counteract oxidative stresses such as bronchopulmonary dysplasia and necrotizing enterocolitis.
Determination of the transverse propagation delays in single-gate GaAs Mesfets

A computer-efficient algorithm for the calculation of the transverse propagation delays in single-gate GaAs MESFETs is presented. Electrode parasitic capacitances and the electrode contact and metallization resistances have been included in addition to the internal elements in the MESFET. The technique can be used for MESFETs with submicron gate lengths as well.
A Stereoselective Vanadium-Dependent Chloroperoxidase in Bacterial Antibiotic Biosynthesis

Halogenases catalyze reactions that introduce halogen atoms into electron-rich organic molecules. Vanadium-dependent haloperoxidases are generally considered to be promiscuous halogenating enzymes that have thus far been derived exclusively from eukaryotes, where their cellular function is often disputed. We now report the first biochemical characterization of a bacterial vanadium-dependent chloroperoxidase, NapH1 from Streptomyces sp. CNQ-525, which catalyzes a highly stereoselective chlorination-cyclization reaction in napyradiomycin antibiotic biosynthesis. This finding biochemically links a vanadium chloroperoxidase to microbial natural product biosynthesis.
Use of nonsteroidal anti-inflammatory drugs and reduced breast cancer risk among overweight women

Chronic inflammation is associated with increased risk of multiple cancers, including breast cancer. Adipose tissues produce proinflammatory cytokines, and obesity is a risk factor for postmenopausal breast cancer. We evaluated the association of regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) with breast cancer risk, overall and by body mass index (BMI) and tumor subtypes defined by estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status. We conducted a population-based, case-control study involving 5,078 women aged 25-75 years who were recruited primarily from the Nashville metropolitan area of Tennessee. Multivariate unconditional logistic regression models were used to estimate odds ratios and 95 % confidence intervals for breast cancer risk after adjusting for multiple potential confounding factors. Regular use of any NSAID was associated with significantly reduced breast cancer risk (OR 0.78; 95 % CI 0.69-0.89). This association was observed for regular use of baby aspirin only (OR 0.82, 95 % CI 0.69-0.99), other NSAIDs only (OR 0.81, 95 % CI 0.69-0.95), and both baby aspirin and other NSAIDs (OR 0.52, 95 % CI 0.40-0.69). These significant inverse associations were found among overweight women (BMI ≥25 kg/m(2)) overall and by subtypes of breast cancer, but not among women with BMI <25 kg/m(2) (P for interaction = 0.023). Regular use of NSAIDs was inversely associated with breast cancer risk, particularly among overweight women. Overweight women may benefit more from the protective effects of NSAID use than normal-weight women.
Systematic Variation of Quadrupole Crystal-Field Shielding in Rare-Earth Ethyl Sulfates

Quadrupole-coupling constants were obtained from measurements on ${\mathrm{La}}^{140}$, ${\mathrm{Eu}}^{154}$, ${\mathrm{Gd}}^{159}$, and ${\mathrm{Lu}}^{177}$ nuclei oriented in neodymium ethyl sulfate at temperatures down to 0.01\ifmmode^\circ\else\textdegree\fi{}K. These results are combined with the other available quadrupole-coupling data on La, Dy, Tm, and Lu in ethyl sulfate lattices to determine the quadrupole-antishielded term transforming as ${{Y}_{2}}^{0}$ in the crystal-field potential, i.e., $(1\ensuremath{-}{\ensuremath{\gamma}}_{\ensuremath{\infty}}) {{A}_{2}}^{0}$. This term increases fairly slowly throughout the rare earths, with an average value of approximately $(3\ifmmode\times\else\texttimes\fi{}{10}^{4} {\mathrm{cm}}^{\ensuremath{-}1}){{a}_{0}}^{\ensuremath{-}2}$. These values were compared with theoretical estimates of -80 for ${\ensuremath{\gamma}}_{\ensuremath{\infty}}$ to yield the quantities ${{A}_{2}}^{0}$. Comparison of the ${{A}_{2}}^{0}$'s with the corresponding ${{V}_{2}}^{0}$'s taken from optical spectroscopy, using Hartree-Fock radial moments $〈{r}^{2}〉$ for the $4f$ electrons, together with some extrapolation, gives a complete set of shielding factors ($1\ensuremath{-}{\ensuremath{\sigma}}_{2}$) for the crystal-field component ${{V}_{2}}^{0}$. These factors vary from 0.6 in ${\mathrm{Lu}}^{3+}$ to 0.4 in ${\mathrm{Eu}}^{3+}$ and drop to -0.2 in ${\mathrm{La}}^{3+}$. Thus not only is there substantial shielding of ${{V}_{2}}^{0}$, but this shielding seems to vary considerably in the $4f$ series. The ${\ensuremath{\sigma}}_{2}$'s are typically larger by about 50% than theoretical estimates.
Free energy (chemomechanical) transduction in elastomeric polypeptides by chemical potential modulation of an inverse temperature transition

Data and analyses are presented on the first synthetic polypeptide system to exhibit mechanochemical coupling; the mechanochemical coupling can also be demonstrated to be both polymer-based and solvent-based with respect to where the result of the change in the chemical potential is focused. Both polymer-based and solvent-based processes are the result of chemomechanical transduction in which the change in chemical potential results in a change in the temperature at which an inverse temperature transition occurs. In the polymer-based process, the contraction/relaxation occurs due to a change in the chemical nature of the polypeptide; in the solvent-based process there is no change in the chemical nature of the polypeptide on contraction or relaxation, but rather the change in chemical potential changes the state of hydration of the polypeptide. The new mechanochemical system provides an experimental system with which to clarify and to quantitate what may be called aqueous mediated apolar–polar interaction energies in polypeptides and proteins with hydrophobic groups that may be variously exposed to the aqueous solution or buried within the folded polypeptide or protein. Furthermore, it is noted that any conformational change exhibited by a polypeptide or protein that is the result of a binding of a chemical moiety, the change in chemical nature of a bound moiety or the change in chemical potential of the medium can be viewed in terms of mechanochemical coupling or chemomechanical transduction.
Antisense oligonucleotide mediated knockdown of HOXC13 affects cell growth and induces apoptosis in tumor cells and over expression of HOXC13 induces 3D-colony formation.

HOXC13 is a homeobox containing gene that plays crucial roles in hair development and origin of replication. Herein, we investigated the biochemical functions of HOXC13 and explored its potential roles in tumor cell viability. We have designed a phosphorothioate based antisense-oligonucleotide that specifically knockdown HOXC13 in cultured cells. Cell viability and cytotoxicity assays demonstrated that HOXC13 is essential for cell growth and viability. Antisense-mediated knockdown of HOXC13 affected the cell viability and induced apoptosis in cultured tumor cells. HOXC13 regulates the expression of cyclins and antisense-mediated knockdown of HOXC13 resulting in cell cycle arrest and apoptosis in colon cancer cells. Finally over expression of HOXC13 resulted in 3D-colony formation in soft-agar assay indicating its potential roles in cell proliferation and tumorigenesis.
Convergence Properties of Wavelet Series Expansions of Fractional Brownian Motion

Abstract We consider the approximation of a fractional Brownian motion by a wavelet series expansion at resolution 2−l. The approximation error is measured in the integrated mean squared sense over finite intervals and we obtain its expansion as a sum of terms with increasing rates of convergence. The dependence of the coefficients in the expansion of the error on the scale function is explicitly determined.
A note on bias robustness of the median

Abstract In this article, it is proved that the median is a minimax bias functional (with respect to many distances including the Kolmogorov distance) among all location equivariant functionals if the distribution of interest is symmetric and unimodal. This is a parallel result of Huber's well-known result (1964). We also proved that the median is no longer a minimax bias functional with respect to several definitions of bias including the contamination bias if the symmetry assumption is violated.
Chloramphenicol-resistant mutants of human HeLa cells.

Chloramphenicol is one of a number of antibiotics which specifically inhibit mitochondrial protein synthesis in eukaryotic cells, while not affecting the cytoplasmic system [ 1,2]. Some mutations conferring resistance to chloramphenicol could directly affect the mitochondrial protein synthesizing system. Studies of respiratory-deficient mutants of yeast and of Neurospora have shown that mitochondrial proteins are products of both cytoplasmic extrachromosomal determinants and of chromosomal genes [3]. The Neuro spora poky mutation, which affects mitochondrial ribosomes, exhibits nonMendelian inheritance [4]. The existence of erythromycin-, mikamycin-, and chloramphenicol-resistant yeast mutants which likewise show cytoplasmic inheritance [5-S] suggest that, in mammalian cells also, resistance to chloramphenicol may be mitochondrially coded. Extrachromosomally inherited mitochondrial mutations in mammalian cells are essential to determine gene locations of mitochondrial proteins and to study nuclear-mitochondrial interactions in mitochondrial biogenesis. This paper describes the isolation and general properties of mutants of human HeLa cells resistant to chloramphenicol.
A tribute to Donald J. Willower

Describes attributes of Donald J. Willower from the viewpoint of a fellow professor at Pennsylvania State University. Identifies Willower as a leader in the field of educational administration and as an outstanding teacher and researcher. Willower’s fame helped establish and maintain Pennsylvania State University as a leading institution in the USA. Notes also Willower’s continuing support for the scientific approach to research in the field.
Cocaine: excitatory effects on sensorimotor reactivity measured with acoustic startle.

Cocaine (2.5–10 mg/kg) caused a dose-related increase in the amplitude of the acoustic startle reflex in rats. In contrast, procaine (5–40 mg/kg) caused a dose-related decrease in startle, indicating that the effects of cocaine could not be ascribed to its local anesthetic effects. Cocaine's excitatory effects were blocked by pretreatment with haloperidol (0.5 mg/kg) but not by cyproheptadine or prazosin. The excitatory effects of cocaine (10 mg/kg) were markedly attenuated by pretreatment with reserpine (5 mg/kg 24 and 18 h earlier) but not by α-methyl-p-tyrosine (100 mg/kg 1 h earlier). In contrast, comparably sized excitatory effects of d-amphetamine were blocked by α-methyl-p-tyrosine and greatly enhanced by pretreatment with reserpine. Neither pretreatment blocked excitatory effects of apomorphine on startle. The data indicate that cocaine increases startle by acting through reserpine-sensitive pools of dopamine and provide further support for the conclusion that acoustic startle is enhanced by activation of dopamine receptors.
Sex preselection in mammals? Separation of sperm bearing Y and "O" chromosomes in the vole Microtus oregoni

The two sex determining sperm populations of the vole Microtus oregoni were separated according to DNA content by use of flow sorting instrumentation. Although the sperm were not viable, they should be useful for addressing the question of haploid expression of genes linked to sex chromosomes and for efficiently searching for biochemical markers that differentiate the two populations.
A novel clinical application for endoscopic mucosal clipping.

Abstract Background: Endoscopic hemoclipping has been shown to be effective in the treatment of gastrointestinal bleeding. Here we describe a novel clinical application for endoscopic application of metal clips. Methods: A middle-aged man with inoperable squamous cell cancer of the esophagus underwent per protocol a barium esophagogram to document tumor margins prior to radiation therapy. This study failed to localize the full extent of the tumor. At endoscopy, the tumor margins were clearly visible. To delineate the proximal and distal margins, detachable metallic clips were passed through the accessory channel of a standard endoscope and using a clip fixing device the clips were placed at each level. Subsequently, a chest x-ray was obtained. Results: Placement of mucosal clips facilitated radiotherapy. Conclusions: Endoscopic mucosal clipping may serve as a useful technique for localizing or marking gastrointestinal lesions, especially for demarcating a precise radiation field when conventional techniques fail.
Stochastic forcing models of climate variability

Hasselmann (1976) has recently proposed a stochastic model of climate variability where climatic changes are caused by the intrinsic variability of the weather fluctuations. The complete atmosphere--ocean--cryosphere-land system is separated into long time scale "cl imate" components (mainly the ocean and the cryosphere) and short time scale "wea ther" components (mainly the atmosphere). The weather components exhibit stochastic fluctuations with a dominant t ime scale of a few days, reflecting instabilities of the atmospheric circulation. Because of their much larger time scale, the climate components respond essentially as integrators of the atmospheric forcing, which acts as an "internal" white noise generator. The random-walk climate fluctuations that develop have a variance which grows linearly with time, until feedback processes become important and lead eventually to a statistically stationary climate state. A red frequency spectrum is predicted for the climate variance, in general agreement with observations over a broad range of time scales, as reviewed below (see also Mitchell, 1976). The general theory is given in Hasselmann (1976). Here we shall introduce the formalism in the simpler context of sea surface temperature anomalies, and present new comparisons of the model predictions with observations in the North Pacific. It is shown that a single model reproduces the principal features and the seasonal variability of the large-scale sea-surface temperature anomalies observed in mid-latitudes. Other applications of the stochastic climate models are then reviewed. Quasi-geostraphic motions in the ocean interior and yearly and zonally averaged world temperature fluctuations induced by the natural variability of the atmosphere are discussed. The magnitude of
STAT: a saccharide topology analysis tool used in combination with tandem mass spectrometry.

Sequential stages of mass spectrometry (MSn) have the potential to provide a great deal of structural information in glycan analysis. The saccharide topology analysis tool (STAT) presented here is a Web-based computational program that can quickly extract sequence information from a set of MSn spectra for an oligosaccharide of up to 10 residues. After information such as precursor ion mass, possible monosaccharide moieties, charge carrier, and product ion mass has been input, all possible connectivities are generated and evaluated against the MSn data. The list of possible structures is given a rating based on the likelihood that it is the correct sequence. Examples are given to demonstrate the feasibility of applying STAT to MSn data generated from bacterial lipooligosaccharides and an N-linked glycan. The major advantage of STAT is that the list of possible structures is generated quickly and the rating system pushes the more likely structures to the top of the list. Combining the data generated by STAT...
In vivo quantification of microglia dynamics with a scanning laser ophthalmoscope in a mouse model of focal laser injury

Microglia are the resident immune cells of the central nervous system and play a crucial role in maintaining neuronal health and function. Their dynamic behavior, that is, the constant extension and retraction of microglia processes, is thought to be critical for communication between microglia and their cellular neighbors, such as neurons, astrocytes and vascular endothelial cells. Here, we investigated the morphology and dynamics of retinal microglia in vivo under normal conditions and in response to focal laser injury of blood vessel endothelial wall, using a scanning laser ophthalmoscope (SLO) designed specifically for imaging the retina of live mice. The multichannel confocal imaging system allows retinal microstructure, such as the processes of microglia and retinal vasculature, to be visualized simultaneously. In order to generate focal laser injury, a photocoagulator based on a continuous wave (cw) laser was coupled into the SLO. An acousto-optic modulator chopped pulses from the cw laser. A tip-tilt-scanner was used to direct the laser beam into a blood vessel of interest under SLO image guidance. Mild coagulation was produced using millisecond-long pulses. Microglia react dynamically to focal laser injury of blood vessel endothelial walls. Under normal conditions, microglia somas remain stationary and the processes probe a territory of their immediate environment. In response to local injury, process movement velocity approximately doubles within minutes after injury. Moreover, the previously unpolarized process movement assumes a distinct directionality towards the injury site, indicating signaling between the injured tissue and the microglia. In vivo retinal imaging is a powerful tool for understanding the dynamic behavior of retinal cells.
Mersilene mesh sling: Short- and long-term clinical and urodynamic outcomes

Abstract Objective: We sought to determine the long-term efficacy, safety, and urodynamic effects of the Mersilene mesh suburethral sling in treating complicated forms of genuine stress incontinence. Study Design: Two hundred women diagnosed with genuine stress incontinence, complicated by recurrence, intrinsic sphincter deficiency, or chronically increased intraabdominal pressure underwent a suburethral mesh sling procedure (Mersilene; Ethicon Inc, Somerville, NJ). They were monitored with yearly clinical examinations plus short- and long-term postoperative urodynamic evaluations; statistical analysis was carried out by use of the Friedman 2-way analysis by rank, Fischer-Freeman-Halton exact testing, analysis of variance for repeated measures, Wilcoxon, exact Mann-Whitney U test, and Bonferroni paired t test. Of 176 patients who were 5 months or more postop, 127 (72%) had preoperative and short-term postoperative urodynamic evaluations (range 5 to 23 months, mean 12.6 months). Fifty-two of 117 women who were more than 19 months postop (44%) completed preoperative and long-term postoperative urodynamic evaluations at a mean of 63 months (range 20 to 107). One hundred thirty-six of 176 patients (77%) who were more than 4 months postop had a short- and/or long- term postoperative urodynamic evaluation (range 5 to 107 months, mean 30 months). Results: Objective cure rate by stress test was 93% (126 of 136 patients) at a mean of 30 months follow-up. The long-term objective cure rate was 94% (49 of 52). Subjectively, the short- and long-term cure rates were 95.3% and 90.4%, respectively. The cotton swab angle deflection decreased by a mean of 54 degrees at 1 year and 50 degrees at 5 years. Of the 10 failures, the mean preoperative cotton swab straining angle was 19.6 degrees, with 6 being Conclusions: The suburethral Mersilene mesh sling has a very high long-term objective and subjective cure rate in the treatment of complicated forms of genuine stress incontinence. Frequent complications do occur but are remediable. The 33% failure rate among patients with a preoperative negative cotton swab angle test result and the very low cotton swab straining angle among the 7% who had sling failures further confirms the widely held belief that sling urethropexy in the absence of hypermobility lacks efficacy. (Am J Obstet Gynecol 2001;185:32-40.)
On the origin and early evolution of terrestrial planet atmospheres and meteoritic volatiles

A simple analytic model of mass fractionation in hydrodynamic escape is applied to the problem of the origin and evolution of terrestrial planet atmospheres and meteoritic noble gases from primordial compositions. It is shown that isotopic distributions of xenon, krypton, argon, and neon on Earth can be generated by two stages of hydrodynamic loss, first of a hydrogen-rich, isotopically solar primitive atmosphere, and then of Kr, Ar, and Ne subsequently outgassed from deep within the planet. Degassed species are also isotopically solar, and their required elemental fractionation pattern is in reasonable agreement with laboratory adsorption experiments
An Experimental Design for Outplanting Nursery Trials on Heterogeneous Sites

SYNOPSIS The selection of the field design for outplanting a nursery study is determined by the researcher's objectives and, to some extent, the heterogeneity of the outplanting site. Square (or almost square), multiple-tree plots are recommended for long-term studies, but owing to the size of replications, large uniform sites are required to minimise variability within replications. Large uniform areas may be difficult to locate on many forest sites. However, when using single-tree plots for short-term outplanting studies, replications are much smaller and the site selected need not be as homogeneous. This paper describes the advantages and disadvantages of using single-tree plots for field evaluation of nursery treatments.
Flow Characteristics of a Steam-Injection Vacuum Pasteurizer

Summary Tests were made to determine the extent of spreading of a salt charge as it passed through a vacuum pasteurizer. All tests were conducted with the equipment operating on tap water at a flow rate of 4,010 ± 10 lb per hour. Spreading of the salt charge was detected by instantaneously measuring the conductivity of the liquid as it passed a downstream electrode. A high-speed motion picture camera operated at 64 frames per second simultaneously recorded ammeter, voltmeter, and electric timer readings on 16-mm film. The sensing electrodes were placed beneath the first chamber and immediately after the product removal pump of the second chamber of the ultrahigh-temperature unit. The salt charge was injected into the flow immediately before the steam injector. The time differential between the slowest and fastest particles was about 5 sec when the salt charge left the first chamber and it increased to 10.6 sec at the discharge side of the product removal pump of the second chamber.
BRIDGING THE GAP: INFLUENCE OF SEED DEPOSITION ON SEEDLING RECRUITMENT IN A PRIMATE–TREE INTERACTION

Frugivores are thought to influence plant recruitment by creating initial seed deposition templates. However, post-deposition processes (e.g., predation) may obscure these initial patterns. Few studies have examined successive life-history stages of animal-dispersed plants to evaluate how initial frugivore seed deposition influences early life stages of plant recruitment. We addressed this issue by quantifying seed removal and seedling recruitment of Monodora myristica (Annonaceae), a tropical, low-fecundity, forest tree in Kibale National Park, Uganda. Fruit morphology suggests that this species is dispersed by only the largest arboreal frugivores. We determined which frugivores removed fruit during focal tree watches and quantified seed fate in experiments designed to mimic natural deposition. We estimated stage-specific transition probabilities of survivorship to seedling establishment and determined expected seedling recruitment from each deposition condition. To evaluate spatial and temporal variation, these methods were conducted at two sites, 15 km apart, over two years. Finally, we compared frugivore abundance between sites to expected seedling and standing seedling, sapling, and pole abundances. We found that large-bodied primates were critical for seed dispersal. They were the only frugivores that opened the hard-husked fruits and were estimated to disperse >85% of mature seeds. Seeds placed away from parents had higher germination and establishment probabilities than those under parents, indicating that seed dispersal is advantageous. Single seeds away from parents (mimicking small-bodied primate seed spitting) had the highest cumulative seedling recruitment probability. However, in three of four site-by-year combinations, 86–94% of estimated recruits came from seeds placed in clumps in dung (mimicking large-bodied primates). High recruitment in the latter condition is due to the large number of seeds estimated to be deposited by large-bodied primates. Despite this concordance, germination and establishment probabilities were highly variable between sites and years. Germination was a limiting step in recruitment, and high seed mortality from beetles and rodents indicates the importance of predation. The site with higher frugivorous primate abundance had higher standing seedling abundance, but lower expected seedling recruitment and lower sapling and pole abundances. Thus, even in a system where frugivores are critical for dispersal, spatial and temporal variation in post-deposition processes reduces predictability of frugivore actions on seedling recruitment. Corresponding Editor: E. S. Menges
Independent external review of health maintenance organizations' medical-necessity decisions.

A patient who was denied coverage for a specialized surgical procedure successfully sued her health maintenance organization (HMO). In its appeal to the U.S. Supreme Court, the HMO argued that as a...
On the Distinctness of the Fiddler Crabs Uca Minax (Leconte) and Uca Longisignalis Salmon & Atsaides in Their Region of Sympatry (Decapoda Brachyura, Ocypodidae)1)

Uca longisignalis is morphologically and ecologically distinct from all fiddler crab species in the western Atlantic. In particular, it is obvious among the congeners U. pugnax and U. minax. It shows an affinity for the minax-superspecies grouping within the Minuca subgenus (Crane, 1975). Since Von Hagen (1980) had access to few U. longisignalis and little information concerning the ranges of species within the Gulf of Mexico, his evolutionary considerations may be premature. The tomentum of the carapace and ambulatories (Von Hagen, 1970b) may offer little precision in evaluating the evolutionary origins of this species. On the one hand, ambulatory pubescence may aid a relatively terrestrial species to absorb and retain water in semi-arid and sub-humid habitats like those in the western Gulf (Hedgpeth, 1953). On the other, carapace tomentum like that found in U. vocator, U. speciosa or U. thayeri may enhance transevaporative water loss and be deleterious in these environments. Due to the degree of terrestriality expressed by U. longisignalis, it has been relatively successful in adjusting to non-marine environments. Consequently, it may be possible for a species to evolve and adapt to new biomes by maintaining or dispensing with primitive characters depending upon their fortuitous value in a newly invaded habitat. The exact relationship of Minuca species to each other is not clear. Within this subgenus, Uca longisignalis appears to be more closely related to a burgersi-mordax-minax-pugnax lineage than a galapagensis-herradurensis-marguerita-rapax grouping as suggested by Crane's treatment (1975). We have no conclusive evidence as to whether Gulf species are recently evolved or represent relic species from the lower Tertiary. In a geological perspective, Uca minax has been successful in maintaining a post-glacial disjunct distribution and, perhaps, represents a form older than either U. longisignalis or U. pugnax. Since the Gulf of Mexico began forming through tectonic activity at least 165 mybp (White, 1980) and apparently reached its present equilibrium during the late Miocene and early Quaternary, 13 mybp (Carey, 1963), the congruent distributions of five endemic species of fiddler crab within the Gulf of Mexico (Barnwell & Thurman, in preparation) appear to support a recent origins hypothesis. Otherwise, one would expect to observe more than one species of North American fiddler crab to exhibit a Carolinian-like distribution.