cssi/SciSciGPT-SciSciNet huggingface dataset:
Correlation of the Genetic Map and the Endonuclease Site Map of Bacillus subtilis Bacteriophage SP02

By marker rescue of bacteriophage SP02 sus mutants with purified bacteriophage SP02 DNA fragments, 11 of the 17 known bacteriophage SP02 sus loci were assigned to discrete DNA fragments. The left-most genetic locus, susA, was found to reside near one bacteriophage SP02 terminus (EcoRI-C1 fragment), whereas the right-most genetic locus, susP, was found to reside near the other bacteriophage SP02 terminus (EcoRI-C2 fragment). The physical locations of the intervening genetic loci were found to be consistent with the previously determined genetic order. Evidence was also obtained which suggested that at least one end of a transforming DNA fragment is degraded during DNA uptake by the competent bacterium.
The effects of controlling capture on multimedia traffic for shared Ethernet systems

The IEEE 802.3 Ethernet standard is evolving to support much higher data rates and improved quality of service. Even low cost half?duplex CSMA/CD networks can be improved using an enhanced backwards?compatible collision arbitration algorithm known as the Binary Logarithmic Arbitration Method (BLAM) now being proposed as the IEEE 802.3w draft standard. BLAM is designed to co?exist fairly with the existing Binary Exponential Backoff (BEB) algorithm, while eliminating its short?term unfairness problems. In this paper, we focus on how BLAM improves Ethernet performance for multimedia data transport. Analytical, simulation, and prototype hardware experimental results using synthetic, trace, and actual measured traffic are presented. It is shown that BLAM Ethernets can support significantly greater numbers of video streams than existing BEB Ethernets and if the delivery requirements for the video traffic are not too strict, that BLAM Ethernets can even support video if the network is completely saturated with data traffic.
Processing of the papain precursor. Purification of the zymogen and characterization of its mechanism of processing.

The precursor of the cysteine protease papain has been expressed and secreted as propapain from insect cells infected with a recombinant baculovirus expressing a synthetic gene coding for prepropapain. This 39-kDa secreted propapain zymogen molecule is glycosylated and can be processed in vitro into an enzymatically active authentic papain molecule of 24.5 kDa (Vernet, T., Tessier, D.C., Richardson, C., Laliberte, F., Khouri, H. E., Bell, A. W., Storer, A. C., and Thomas, D. Y. (1990) J. Biol. Chem. 265, 16661-16666). Recombinant propapain was stabilized with Hg2+ and purified to homogeneity using affinity chromatography, gel filtration, and ion-exchange chromatographic procedures. The maximum rate of processing in vitro was achieved at approximately pH 4.0, at a temperature of 65 degrees C and under reducing conditions. Precursor processing is inhibited by a variety of reversible and irreversible cysteine protease inhibitors but not by specific inhibitors of serine, metallo or acid proteases. Replacement by site-directed mutagenesis of the active site cysteine with a serine at position 25 also prevents processing. The inhibitor 125I-N-(2S,3S)-3-trans-hydroxycarbonyloxiran-2-carbonyl-L-tyrosine benzyl ester covalently labeled the wild type papain precursor, but not the C25S mutant, indicating that the active site is accessible to the inhibitor and is in a native conformation within the precursor. Based on biochemical and kinetic analyses of the activation and processing of propapain we have shown that the papain precursor is capable of autoproteolytic cleavage (intramolecular). Once free papain is released processing can then occur in trans (intermolecular).
Virulence-Linked Bacteriophages of Pathogenic Vibrios

This chapter focuses on the bacteriophages of pathogenic vibrios, particularly those that have been found to contribute directly to bacterial virulence. These phages primarily target Vibrio cholerae; however, a virulence-associated phage found in V. parahaemolyticus is also discussed briefly. V. cholerae O139 appears to have evolved from an O1 El Tor strain that acquired a new cassette of genes for O antigen production. Whether the emergence of O139 as a widespread etiologic agent of cholera marks the beginning of a new, eighth cholera pandemic is being debated. The 5’ end of the prophage (-2.4 kb) is known as the RS region. It encodes proteins needed for phage gene regulation (RstR), phage replication (RstA), and phage DNA integration (RstB). Genetic studies indicate that at least two protein complexes are used by CTXφ to infect V. cholerae. Toxin-coregulated pilus (TCP), a homopolymer of TcpA, is thought to be CTXφ’s primary receptor. A hybrid Fd phage that displays the N-terminal and central domains of pIIICTX on its surface was able to infect V. cholerae, suggesting that pIIICTX is the only CTXφ protein that is needed for normal recognition and infection of its host. Studies of the lysogenic filamentous phage have yielded knowledge of new types of virus-host interactions. The authors anticipate that future studies of CTXφ will provide additional examples of how a virus and its host can coevolve in a symbiotic fashion. Furthermore, it seems likely that future studies of other pathogenic vibrios will uncover new bacteriophages that influence pathogenicity.
Arachidonate metabolic pathways in cells harvested from rat pleural cavity at various times after carrageenan administration

Abstract Cells were harvested from rat pleural cavity before and during the inflammatory response stimulated by carrageenan injection. The conversion of [ 14 C]arachidonate by intact cells into products of the cyclooxygenase and 5-lipoxygenase pathways was studied in the absence and presence of ionophore Incorporation of arachidonate into phosphatidic acid was also followed. In the absence of ionophore, the principal arachidonate metabolites of resident macrophages were the cyclooxygenase products, prostacyclin and thromboxane, while mobilized monocytes produced thromboxane as a major product, but very little prostacyclin. Arachidonate-metabolizing enzymes in mobilized monocytes were, in general, less active than those of resident macophages. Cells harvested at times when mobilized neutrophils were the predominant cell type were capable of converting arachidonate into thromboxane and prostaglandins, but not prostacyclin. These cells exhibited the most active turnover of arachidonate into phosphatidic acid, and the extent of this turnover appeared to be temporally related to the presence of edema in the pleural cavity at the time of cell harvest. Enzymatic formation of 5-lipoxygenase products was dependent on calcium and was markedly stimulated by ionophore A23187 in both resident and mobilized pleural cells. Among several non-steroidal drugs tested, cyclooxygenase inhibitors were the most effective in preventing the inflammatory response in the carrageenan model of inflammation.
An open-label pilot study of alefacept for the treatment of pyoderma gangrenosum

Background Pyoderma gangrenosum (PG) is a chronic inflammatory disease that causes painful cutaneous ulcers that are difficult to treat. Currently, systemic immunosuppressants, often including prednisone, are the mainstay of therapy. Long-term therapy with these agents is often required which exposes patients to possible adverse effects. An alternative treatment that is safe and effective is truly needed. Objective To study the efficacy and safety of alefacept, which inhibits T-cell activation and selectively reduces the T-cell population, for treatment of PG. Method In this prospective open-label pilot study, four patients diagnosed with PG received weekly doses of 15 mg alefacept intramuscularly for 20 weeks with 12-week treatment-free follow-up. The primary efficacy end point was the proportion of patients achieving remission as defined by a Physician Global Assessment (PGA) of ‘clear’ or ‘almost clear.’ Secondary endpoints included proportion of patients achieving 50% improvement in PG lesion size (measured in mm) and proportion of patients achieving resolution of inflammation (an erythema score of 0 and a border thickness of 0 on scales of 0–4). Results By week 20, one (25%) of the four patients achieved remission, two showed marked improvement in severity on PGA, and one had slight improvement. One patient showed a 98% decrease in lesion size; two other patients evidenced a decrease in the number of small lesions as well as improvements in primary lesion sizes, but did not surpass the 50% criterion. All four patients showed improved erythema scores during treatment, though only one patient showed a complete resolution of inflammation. Limitations It may be difficult to generalize the results of this study to a larger population of patients with PG due to the small sample size and lack of a control group. A longer treatment interval might have been required. Safety and efficacy of long-term therapy is unknown. Conclusion In this pilot study it appears that alefacept treatment may significantly reduce PG severity levels as evidenced by improvement in PGA, Subject Global Assessment, and inflammation scores in all patients. Alefacept may be a safe and effective alternative to current systemic immunosuppressants used to treat PG. Double-blinded, controlled trials are necessary to further evaluate the safety and effectiveness of this treatment.
Adirondack Headwater Lake Chemistry Relationships with Watershed Characteristics

The Adirondack Region of New York State has been identified as having surface waters sensitive to acidic deposition and as receiving large annual inputs of acidic deposition. The large amount of data available for this region makes a quantitative study of the region possible. Compiled from a variety of sources, the Adirondack Watershed Data Base (AWDB) contains information on lake chemistry; lake elevation, area, and volume; and associated watershed data, such as size, slope, aspect, elevation, vegetation and wetland types, beaver activity, fire and logging history, and soils data. Bivariate and multivariate procedures were used to examine relationships between watershed attributes and lake chemistry. Because the variables in the data base are being refined and modified, the current relationships should be considered preliminary. Preliminary results indicate that wet deposition, lake elevation, and forest cover are the principal variables that are associated with variance in the data for lake pH and acid neutralizing capacity (ANC) in the Adirondacks. For headwater lakes in the Adirondacks, we estimate approximately 50% have a total ANC ≤ 40 μeq L−1 and 40% have a pH ≤ 5.5.
Hierarchical and rhythmic organization in the songs of humpback whales (Megaptera novaeangliae)

Since the groundbreaking work of Payne and McVay (1971), humpback songs have been conceptualized in terms of the upward hierarchical organization of sound units within phrases, and phrases within themes. Songs change within each season and all whales in a geographical region detect and sing the reshaped song. Here we propose two properties that act to make relearning the evolving song possible. First, each level of the hierarchical structure constrains the others. We estimated the degree of constraint using information theory and found that the theme, phrase, and prior sound unit reduced the source entropy of the current sound unit equally. Different sound units are found in each theme and phrase; each theme and phrase ‘uses up’ some of the sound units. Second, the rhythm of the sound units acts to simplify the phrase structure. The timing between sound units often separates adjacent phrases by longer silent durations, and in spite of huge differences in the number of sound units within phrases, the overa...
Spatial Discrimination in Three-Dimensional Displays as a Function of Computer Graphics Eyepoint Elevation and Stereoscopic Viewing

In this study we investigate the effects of computer graphics eyepoint elevation, display type (perspective vs. stereoscopic), and location of computer-generated images within a particular quadrant on the accuracy of spatial judgments. Twelve volunteer participants judged the azimuth and elevation separation between two computer-generated cubes using different computer graphics eyepoint elevation angles and either a stereoscopic or perspective display. The results indicated that eyepoint elevations between 15|dG and 45|dG led to the best overall performance for judgments of both elevation and azimuth. Whereas an eyepoint elevation of -15|dG resulted in significantly degraded judgments in azimuth because of depth compression, an eyepoint elevation of 75|dG resulted in significantly degraded judgments in elevation because of vertical compression. Furthermore, when objects were located in the quadrant closest to the computer graphics eyepoint, significant degradation in elevation judgments were observed beca...
Does abdominal body composition modulate the effects of back belts on the respiratory system

Abstract This study examines the hypothesis that abdominal body composition may modulate the effects that back belts have upon the respiratory function of the wearer. Twelve subjects were divided into two groups based upon abdominal skinfold thickness. Respiratory parameters were compared between groups, between belt-wearing conditions, and between activity levels. Tidal volume ( V T ) and respiratory frequency ( f ) were monitored at rest; during a repetitive lifting task; and during recovery from this lifting task. Forced vital capacity (FVC) and forced expiratory volume (FEV 1 ) were measured during rest and recovery. During exercise, the back belt significantly decreased tidal volume in the high abdominal fat group and increased tidal volume in the low abdominal fat group (Prob> F =0.0002). This study showed no other significant differences in respiratory responses between groups. It is concluded that the abdominal body composition of a given subject can modify the physiological effects of back belts on the respiratory system. It is suggested that abdominal body composition should be controlled for in future studies of the effects of abdominal compression. Relevance to industry Individuals with central obesity and/or preexisting lung disease may experience modifications in lung function that could limit their performance when wearing a back belt. The results of this study, therefore, are relevant to medical practitioners, safety officers, and workers performing manual materials handling tasks.
Low-resistive and homogenous NiPt-silicide formation using ultra-low temperature annealing with microwave system for 22nm-node CMOS and beyond

A novel NiPt-silicide formation using microwave annealing (MWA) is proposed, and superior properties of NiPt silicide in ultra-shallow junction (USJ) are demonstrated for the first time. MWA is suitable for the thin NiPtSi formation with its stable and ultra-low temperature (less than 250 °C) heating. The anomalous Ni diffusion during the NiPtSi formation is considered to be suppressed because MW system heats Si substrates selectively. As a result, low-resistive and homogeneous NiPtSi can be formed, and the increase of the junction leakage current due to the abnormal NiPt-silicide growth is successfully suppressed in USJ. This superior technique is quite promising for achieving 22nm-node CMOS and beyond.
Early literacy individual growth and development indicators (EL-IGDIs): growth trajectories using a large, internet-based sample.

Abstract Early literacy individual growth and development indicators (EL-IGDIs) assess preschoolers' expressive vocabulary development and phonological awareness. This study investigated longitudinal change in EL-IGDIs using a large ( N = 7355), internet-based sample of 36- to 60-month-old United States preschoolers without identified risks for later achievement delays. There were three major findings. First, results identified sensitivity to longitudinal change for all three EL-IGDIs (i.e., Picture naming, Rhyming, and Alliteration). Second, results demonstrated age-related differences in growth rates between 3- and 4-year-olds, especially for Rhyming and Alliteration. Third, preliminary national norms were reported. Discussion highlights the need for research examining the sensitivity of EL-IGDIs for younger preschoolers.
Failure of heat shrinkage for treatment of a posterior cruciate ligament tear

Incomplete tears or traumatic elongations of either the native cruciate ligaments or cruciate ligament reconstructions represent a therapeutic dilemma for orthopaedic surgeons. We report a case of a partially torn posterior cruciate ligament that was treated unsuccessfully with an electrothermal shrinkage procedure. Although the use of thermal energy to selectively shrink tissues may ultimately prove to be an invaluable tool, the lack of well-designed, randomized controlled studies to firmly establish its efficacy in the treatment of partial cruciate injuries mandates cautious use of this technique at this time.
Burden of cervical, anal, and oral HPV in an inner-city pre-vaccine adolescent population.

HPV is the central etiologic agent in cervical and anal cancers and a percentage of head and neck tumors. The FDA-approved prophylactic quadrivalent vaccine (GARDASIL®, Merck & Co., PA) targets the most common types of HPV found in cervical cancers (HPV16/18) and genital warts (HPV6/11).1,2 Current recommendations are to vaccinate young adolescents prior to exposure, after which the vaccine may be much less efficacious.3 However, catch-up vaccination is also underway for women up to the age of 26, and HPV coverage among adolescent females in the U.S.A. is lagging, with only one third having received the full three-dose series.4 Furthermore, while the prevalence of cervical HPV is at its highest in adolescent women, how this relates to other orifices involved in sex (i.e., anal canal and oral cavity) and to vaccine effectiveness in high-risk young women, is the focus of ongoing studies. We set out to assess the prevalence of HPV within the cervix, anal canal, and oral cavity in adolescent women prior to institution of the HPV vaccine from a high-risk inner-city minority population.
Location and housing demand

Abstract William Alonso's model of the demand for housing and location in the monocentric city is one of two pre-eminent models of its type. The purpose of this article is to provide the detailed analysis and the comparative statics of the Alonso model. The complexity of the analysis is seen to derive from the nature of the constraint, which is nonlinear and has slopes which vary with income. A new result is that housing and closeness can be inferior even when they are taste normal. The empirical direct variation of income with distance is explained, consistent with the finding that income increase has indeterminate effects on location and housing demand. The Alonso specification is shown to be superior to others.
Empowering Culturally Diverse Students within a Collaborative Learning Community: A Student Perspective

Psychologists are typically obliged to learn about the cultures of their minority clients and students before working with them, refining their specific cultural knowledge and deepening their understanding of the influence of cultural factors on their clients and students through direct interaction. Likewise, professors of psychology can utilize these principles to empower minority students by (a) modeling cultural openness, (b) acknowledging students' rich cultural knowledge and experiences, (c) tailoring assignments to minority students' culturally influenced learning needs, and (d) seizing teachable moments. Empowering minority students in such a collaborative learning environment allows the burden of incorporating cultural views to shift from minority students to the larger classroom community, in which cultural dynamics may be safely explored, respected, and valued. Although faculty in Orlando's program did their best to accommodate his passion for cross-cultural research and practice, in many courses he found that the inclusion of culture was lacking and he struggled to meet faculty expectations for student participation. Many faculty regarded him as pleasant interpersonally, but they were concerned about his inability to be assertive. Rather than understanding that his passivity and deference to authority were typical of his culture, some criticized him for his limited contributions during class and urged him to engage more. He felt discouraged, isolated, and alone, and contemplated dropping out of his program. As Orlando's experience demonstrates, the experience of being a culturally diverse student within a North American psychology classroom can be difficult, confusing, and culturally isolating. Unfortunately, Orlando's story is not unique: Many culturally diverse students in higher education struggle with similar experiences (see Blackwell, 2010; Case, 2008; Lee & Rice, 2007; Rivera, Forquer, & Rangel, 2010). But why? Although psychology programs often actively recruit culturally diverse students and value diversity, they have difficulty cultivating environments that ensure culturally diverse students are fully integrated into the classroom, succeed in their academic journeys, and obtain the same privileges and opportunities as dominant-culture students (DiAngelo, 2006; Guzman, Trevino, Lubuguin, & Aryan, 2010; Lee & Rice, 2007). In writing this article we drew upon the first author's experience as a Mixteco immigrant in a US clinical psychology graduate program, the dominant-culture-student experience of the second and third authors, and the fourth author's experience as a White male faculty member actively working to integrate international elements into a multicultural graduate classroom. Consequently, we use an extended case example to illustrate the challenges facing culturally diverse students as well as pedagogical methods that may be employed to improve the empowerment of culturally diverse students within the classroom.
A sliding plate normal thrust rheometer for molten plastics

A sliding plate rheometer has been developed to measure the normal thrust of a molten plastic in large amplitude oscillatory shear. The normal thrust of a molten plastic in large amplitude oscillatory shear is a significant nonlinear effect that has previously been unobtainable. Normal thrust measurements may now be used to help understand and characterize nonlinear viscoelastic behavior inherent in most molten plastics. The new rhemoeter incorporates a piezoelectric pressure transducer in a very stiff plate that minimizes compliance. Normal thrust measurements with cone and plate rheometers are made by measuring the total force on the plate (or cone) and are subject to error due to edge effects. The new rheometer measures the local pressure in the sample and is therefore unaffected by sample size or edge effects. Normal thrust measurements in large amplitude oscillatory shear are reported for both molten Phillips TR480 high density polyethylene pipe resin which contains 2% by weight of carbon black filler and IUPAC LDPE X. Crosstalk due to shear stress on the active face of the pressure transducer causes signal error which for oscillatory shear is filtered out using a discrete Fourier transform.
JWST's cryogenic position metrology system

The James Webb Space Telescope will undergo a full system test in the cryogenic vacuum chamber A at the Johnson Spaceflight Center in order to verify the overall performance of the combined telescope and instrument suite. This will be the largest and most extensive cryogenic test ever undertaken. Early in the test system development, it was determined that precise position measurements of the overall hardware would enhance the test results. Various concepts were considered before selecting photogrammetry for this metrology. Photogrammetry has been used in space systems for decades, however cryogenic use combined with the size and the optical/thermal sensitivity of JWST creates a unique set of implementation challenges. This paper provides an overview of the JWST photogrammetric system and mitigation strategies for three key engineering design challenges: 1) the thermal design of the viewing windows to prevent excessive heat leak and stray light to the test article 2) cost effective motors and mechanisms to provide the angle diversity required, and 3) camera-flash life and reliability sufficient for inaccessible use during the number and duration of the cryogenic tests.
913-119 Coronary Angiographic and Doppler Flow Correlates of Technetium-99m Sestamibi Myocardial Perfusion Abnormalities Following Successful Coronary Angioplasty

Thallium-201 myocardial perfusion defects may persist in studies performed early after angiographically successful percutaneous transluminal coronary angioplasty(PTCA), The causes for and frequency of post-PTCA technetium 99m sestamibi (MIBI) perfusion abnormalities have not been elucidated in man, We examined the post-PTCA quantitative coronary angiographic and distal/proximal (d/p) intracoronary Doppler average peak flow velocity (APV) correlates of MIBI myocardial tomography in tie PTCA perfusion beds of 34 consecutive pts (M = 19, F = 15; age = 57 ± 14 yrs), The average pre-PTCA % diameter stenosis [%DS in LAD = 15, RCA = 10, LCX = 6, graft = 3] was 78 ± 15%. Same-day rest-stress MIBI tomograms were blindly scored for the presence and # of reversible myocardial defects in post-PTCA perfusion beds using a 20 segment model. Results of pts with normal (n = 24) and abnormal (n = 10) MIBI scans are compared below: Normal MIBI Abnormal MIBI p value PTCA-Scan Interval (wks) 4.9 ± 3.3 4.2 ± 4.6 NS Post-PTCA %DS (%) 24 ± 11 23 ± 13 NS Min. Luminal Diam. (mm) 2.1 ± 0.5 2.3 ± 0.6 NS d Coronary Flow Reserve 18 ± 0.6 1.6 ± 0.8 NS Post-PTCA dip APV Ratio 12 ± 0.7 06 ± 0.3 0.05 Pts with an abnormal post-PTCA dip APV ratio l 1 had significantly more reversible MIBI defects in the PTCA myocardial perfusion bed (2.5 ± 3.2 vs. 0.2 ± 0.5; p = 0.04). We conclude that MIBI myocardial perfusion defects persist in 29% of pts between 4–5 wks after successful PTCA. The relative post-stenotic flow reduction in these patients suggests a mechanism for post-PTCA reversible perfusion defects beyond abnormal coronary flow reserve and residual stenosis alone.
Acinic cell carcinoma of the cheek

An additional case report of the rare minor salivary gland tumor, acinic cell adenocarcinoma, has been reported. This is the twenty-first case in which the cheek has been the primary site. The tumor was treated by wide local excision and the patient is currently being followed by a large medical center's tumor board.
A method for obtaining digital signatures and public-key cryptosystems

An encryption method is presented with the novel property that publicly revealing an encryption key does not thereby reveal the corresponding decryption key. This has two important consequences: (1) Couriers or other secure means are not needed to transmit keys, since a message can be enciphered using an encryption key publicly revealed by the intented recipient. Only he can decipher the message, since only he knows the corresponding decryption key. (2) A message can be “signed” using a privately held decryption key. Anyone can verify this signature using the corresponding publicly revealed encryption key. Signatures cannot be forged, and a signer cannot later deny the validity of his signature. This has obvious applications in “electronic mail” and “electronic funds transfer” systems. A message is encrypted by representing it as a number M, raising M to a publicly specified power e, and then taking the remainder when the result is divided by the publicly specified product, n, of two large secret primer numbers p and q. Decryption is similar; only a different, secret, power d is used, where e * d ≡ 1(mod (p - 1) * (q - 1)). The security of the system rests in part on the difficulty of factoring the published divisor, n.
Neurotransmitters and neuromodulators in the basal ganglia

The basal ganglia have become a focus for work on neurotransmitter interactions in the brain. These structures contain a remarkable diversity of neuroactive substances, organized into functional subsystems that have unique developmental histories and vulnerabilities in neurodegenerative diseases. A new view of the basal ganglia is emerging on the basis of this neurochemical heterogeneity, suggesting that dynamic regulation of transmitter expression may be a key to extrapyramidal function.
A 2200-Year Record of Permafrost Dynamics and Carbon Cycling in a Collapse-Scar Bog, Interior Alaska

Recent high-latitude warming is increasing the vulnerability of permafrost to thaw, which is amplified by local disturbances such as fire. However, the long-term ecological effects and carbon dynamics are not well understood. Here we present a 2200-year record of pollen, plant macrofossils, testate amoebae, and apparent carbon (C) accumulation rates from two peat cores in a collapse-scar bog (thermokarst) near Fairbanks, Alaska. A black spruce ecosystem with low apparent C accumulation rates existed on the site during the first ~1500 years of the record. We identify two thaw events, which are linked to local fires. Permafrost aggraded rapidly following the first thaw, which we attribute to local vegetation feedbacks and a cooler climate. The second thaw event at 525 cal y BP is preceded by a stand-replacing fire, as evidenced by a drastic decline in Picea and an initial increase in Epilobium, Salix, and ericaceous shrubs, followed by a sustained increase in Populus. Locally, the forest does not recover for more than 100 years, and the site has remained permafrost-free for the last 500 years. Following thaw, average apparent C accumulation rates (60 to >100 g C m−2 y−1) are 5–6 times higher than average boreal C accumulation rates, indicating that peat C accumulation rates can remain substantially elevated for much more than a century following thaw. The low apparent C accumulation for the formerly forested, permafrost peat (<5 g C m−2 y−1) may suggest that C accumulation increases substantially following thaw, but it remains unknown whether deep peat C loss occurred immediately following thaw. Well-preserved Sphagnum peat dominates during this period of rapid accumulation, except for an interval from ~400 to 275 cal y BP which alternates between Sphagnum and vascular plant-dominated peat and wetter, minerotrophic conditions. A decline in Picea pollen during this interval and again ~100 cal y BP suggests a decrease in suitable substrate for tree growth likely attributable to thermokarst expansion on the collapse-scar margin. These findings suggest that the combined effects of fire and thermokarst will result in a long-term reduction of spruce ecosystems in interior Alaska.
Fishing and the Sexual Division of Labor among the Meriam

Do men and women forage differently because they are cooperatively responding to children's requirements for care or because they are differentially sensitive to variance? In this article, I examine how care trade-offs and variance contribute to gender differences in fishing strategies among Torres Strait Islanders (Meriam). Women's fishing had lower failure rates, coefficients of variation, and frequencies of sharing than men's fishing. Men and women responded to trade-offs between mean and variance differently: Women spent less time on high mean–high variance activities, men less time on high mean–low variance activities. Although child-care trade-offs affected time allocation to different fishing activities among women, they did not affect differences in time allocation between the sexes. These results support previous work implicating variance and sharing frequency as important resource currencies shaping gender differences in subsistence decisions, and they offer challenges to a general model of the division of labor predicated on economic notions of specialization as increasing production efficiency.
NCS-MPP (4-(2'-METHOXY-PHENYL)-1-2'-(N-2 -PYRIDYL)-P-ISOTHIOCYANOBENZAMIDO-ETHYL-PIPERAZINE) : A HIGH AFFINITY AND IRREVERSIBLE 5-HT1A RECEPTOR LIGAND

A novel irreversible 5-HT1A receptor binding ligand, NCS-MPP (4-(2'- methoxy-phenyl)-1-[2'-(N-2"-pyridyl)-p-isothiocyanobenzamido]- ethyl-piperazine), based on the new 5-HT1A receptor antagonist p-MPPI (4-(2'-methoxy-phenyl)-1-[2'-(N-2"-pyridyl)-p-iodobenzamido]-ethyl -piperazine ), was synthesized, and its binding characteristics were evaluated using in vitro homogenate binding with rat hippocampal membranes. The Ki value of NCS-MPP was estimated to be 1.8 +_ 0.2 nM using analysis of concentration-dependent inhibition for the binding of [125I]p-MPPI to 5-HT1A receptors. NovaScreen of NCS-MPP showed low to moderate binding affinities to alpha-1, alpha-2-adrenergic and 5-HT2 receptors, with Ki values of 350, 420, and 103 nM, respectively. These data strongly suggest that the ligand bound to 5-HT1A receptors with high affinity and high selectivity. Irreversible inhibition of [125I]p-MPPI binding by NCS-MPP following a 5 min incubation at room temperature was concentration dependent; the inhibition increased to 50% at a concentration less than 10 nM, and became more pronounced (90%) at 400 nM. Under similar assay conditions, NCS-MPP was significantly less efficient in irreversibly inhibiting agonist ligand [125I]8-OH-PIPAT binding to 5-HT1A receptors at lower concentrations (<10nM). After pretreatment of membranes with a low concentration of NCS-MPP (2nM), there was an apparent loss of [125I]p-MPPI binding sites, as expected, but no change in the binding affinity (Kd) was observed. However, the significant increase in Kd at a higher concentration of NCS-MPP (50 nM) indicated that there may be a secondary alkylation site, which may not be directly involved in p-MPPI binding to receptors; nevertheless, it would lead to an increased Kd value. The availability of an irreversible ligand, NCS-MPP, may provide a useful tool for studies of 5-HT1A receptors in the central nervous system.
Helmet Mounted Displays: Evaluation Of Impact On The Operator

The helmet mounted display (HMD) system is designed to facilitate the acquisition of visual information. Instead of requiring gaze shifts to the instrument panel or HUD, specifiable information is available at approximately 0° vertically, and displayed on the helmet visor. Are pilots able to make use of this information without extensive training? If having such information available reduces workload, how does the pilot use the "released" time? To answer these questions, we collected steady state evoked responses (SSEP) to the rapidly flickering display, and also evaluated aspects of visual search as reflected in head and eye movements and eye blinks, in simulated flight. Why these variables are of utility and how they may be used will be described in the context of an evaluation made by our laboratory of the Kaiser HMD system. This was performed for AAMRL/HEA at the McDonnell-Douglas flight simulation facility in St. Louis. Data were collected on B-1 pilots flying "ingress" and "refueling" missions. Although we observed SSEPs in the laboratory, and could record EEG in the electrically noisy simulator environment, several factors prevented a clear demonstration of SSEP under simulation conditions and thus precluded a test of the technique as an index of workload. Specifically, there was less than optimal intensity and waveform of the display, and perhaps most important, there was considerable variablity in the angle of regard of the display due to normal scanning under flight conditions. For purposes of oculographic analysis, the ingress condition was divided into segments associated with approaches to waypoints, threat avoidance, and post-threat periods. Use of the HMD reduced horizontal and vertical visual search activity under all conditions except threat avoidance and post-threat recovery. A second measure, frequency of conjoint occurrence of eye blinks and eye movements, also discriminated the HMD from the nonHMD conditions. Our results suggest that pilots rapidly learn to make effective use of the HMD information, i.e., they spend less time looking at their instrument panels. However, they do not appear to use the "released time" to search their environment more actively.
Sampling distribution of Gini's index of diversity

In the case of a multinomial distribution @P"1([email protected]"1)[email protected]"2([email protected]"2)+...+ @P"k([email protected]"k) is at times referred to as Gini's index of diversity. In this paper, we present the distributional properties of the statistic , based on samples of size n for a homogeneous multinomial distribution. For [email protected][email protected]? 12 and [email protected][email protected]?12, we give a short table of the pdf, cdf, and the moments of D. For large values of n, we mention some results for the asymptotic distribution of D for the general multinomial distribution.
Pyrolysis of aromatic carboxylic acids : Potential involvement of anhydrides in retrograde reactions in low-rank coal

The pyrolysis of 1-(3-carboxyphenyl)-2-(4-biphenyl)ethane (3) has been studied in the liquid phase at 400 °C neat and diluted in hydrogen-donor and nondonor solvents to determine the role of decarboxylation of aromatic carboxylic acids in the cross-linking processes in low-rank coal. Decarboxylation was the dominant reaction pathway in the pyrolysis of this model compound, and decarboxylation occurred primarily by an acid-promoted ionic mechanism that does not lead to cross-linking. However, pyrolysis in a nondonor solvent produced a small amount of products containing a new aryl−aryl bond between 3 and the solvent that represents the formation of a cross-link associated with the decarboxylation process. These cross-linked products were found to be formed by a free-radical pathway and could be decreased by the addition of H2O or tetralin to the pyrolysis medium. It is proposed that the cross-linked products arise from the formation and subsequent decomposition of anhydrides during the pyrolysis of the aci...
REGULATION OF GENE EXPRESSION IN NORMAL AND NEOPLASTIC CELLS

Abstract: We have been studying the regulation of two sets of genetic sequences-histone genes in human cells and AKR C-type viral sequences in mouse cell lines. Histone genes: Recently we observed the presence of two species of H4 histone mRNA on the polysomes of S phase HeLa S 3 cells. Electrophoresis under denaturing and non-denaturing conditions indicate that the two H4 mRNAs differ in size. Both mRNAs translate H4 histones in vitro , lack poly A at their 3′ termini and are capped at their 5′ termini. Polyacrylamide gel electrophoresis and tryptic peptide analysis suggest that the polypeptides synthesized by the two mRNAs are similar. T1 digests of the two H4 mRNAs and two-dimensional fractionation of the resulting oligonucleotides suggest some differences in the nucleotide sequences. The possible biological significance of the two H4 histone mRNAs is discussed. RNA tumor viruses: The expression of AKR C-type RNA tumor virus has been studied in cell lines derived from AKR mouse embryos. Although all AKR cell lines examined contain the proviral sequences integrated into their genomes, viral producer and non-producer lines have been identified. Using a 3H-labeled DNA complementary to AKR viral RNA sequences, the presence of viral RNA sequences in the nucleus and cytoplasm of viral producer cells has been detected. Chromatin from viral producer cells is an effective template for transcription of AKR viral RNA sequences. A significantly reduced level of hybridization is observed between AKR viral cDNA and nuclear RNA, cytoplasmic RNA and in vitro chromatin transcripts from non-producer AKR cells. Regulation of viral gene expression mediated at least in part at the transcriptional level is therefore suggested. The low level of hybridization of viral cDNA with in vivo and in vitro transcribed RNAs from non-producer cells may reflect either partial AKR viral transcripts or other endogenous, closely related C-type viruses. Although chromatins of viral producer and non-producer cells differ in their ability to transcribe AKR viral sequences, high resolution two-dimensional analysis of chromosomal proteins from both cell types does not reveal significant differences.
Relative rates of protein synthesis and reaggregation in embryonic chick liver cells cultured in defined and supplemented media.

Abstract Protein synthesis and aggregate diameters were measured in cultures of 7-day embryonic chick liver cells reaggregating for 20 h in chemically-defined medium and in media supplemented with horse serum and with beef embryo extract. Statistically significant differences were found between defined and supplemented media in the rate of increase of mean aggregate diameters over a 20 h period. However, no statistically significant differences were detected in the rates of cellular protein synthesis in the different media. The results suggest that chemically-defined media are preferable to embryo extract and/or serum-supplemented media for short-term cell aggregation studies.
An optimal foraging-based model of hunter-gatherer population dynamics

Abstract Population changes for hunter-gatherers are modeled on the basis of nutritional intake, which is determined using an optimal foraging model based upon the optimization technique of linear programming. The population model not only demonstrates how hunter-gatherer demography changes with nutrition, but also shows how their density influences food abundance in the environment which in turn affects their nutritional status. Differences in food availability in different environments can be assessed by examining the effects of different preexploitation maxima for food abundances. Hunter-gatherer populations are predicted by the model to display a stable limit cycle which varies in severity with the maximum food abundance in the environment, being more severe at very low and high food abundances. Observed hunter-gatherer densities, growth rates, and life expectancies are shown to be consistent with the population model's predictions for different environments. The model is also used to examine the impact huntergatherers might have on their food resources including whether or not overexploitation (extinction) occurs and how their diets change in different environments with changes in population density. Finally, the model is used to examine archaeological questions about the Paleo-Indian colonization of the New World and the effects of technological innovation by hunter-gatherers.
Probes of a Role for Remote Binding Interactions on Hydrogen Tunneling in the Horse Liver Alcohol Dehydrogenase Reaction

A tunneling contribution to hydride transfer has been demonstrated previously in the oxidation of benzyl alcohol catalyzed by an active-site mutant (F93W) of horse liver alcohol dehydrogenase (LADH) [Bahnson, B. J., et al. (1993) Biochemistry 32, 5503-5507]. Mutation of a residue that lies directly behind the nicotinamide ring of the bound cofactor has further shown that side-chain bulk can contribute to catalytic efficiency and tunneling in a correlated fashion [Bahnson, B. J., et al. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 12797-12802]. Second site mutations of F93W have now been made at positions more remote from the active site. In particular, we have focused on an isoleucine residue that interacts with the adenine moiety of the NAD(+) cofactor, 20 A from the nicotinamide ring. Replacement of this remote residue with glycine (F93W:I224G), alanine (F93W:I224A), valine (F93W:I224V), and leucine (F93W:I224L) is concluded to destabilize the binding of NAD(+). All double mutants exhibited a K(M) for NAD(+) that is 2-25 times higher than that for the F93W enzyme. However, neither the catalytic efficiency for turnover of benzyl alcohol [k(cat)/K(M(benzyl alcohol))] nor the relationship between the secondary k(H)/k(T) and k(D)/k(T) isotope effects for benzyl alcohol oxidation was significantly affected. The lack of differences observed in the isotope effects indicates that these mutations have little effect on the extent of hydrogen tunneling in the reaction. The complete removal of the side chain at position 224 in the F93W:I224G enzyme resulted in a less than 5% decrease in the ratio of the secondary isotope effects, maintaining the ratio above the semiclassical limit for the indication of tunneling in the reaction. By contrast, K(i) for NAD(+) increased 60-fold for this mutant. The results obtained with F93W:I224G are consistent with remote interactions that affect the association and binding of cofactor in a reactive conformation. However, once this conformation is achieved, hydride transfer and its tunneling component proceed as with the single F93W mutant enzyme, uninfluenced by the remote mutation. Replacement of other side chains, with alpha-carbon positions from about 8 to over 20 A from the C4 position of the nicotinamide ring, demonstrated a similar insensitivity of k(cat)/K(M(benzyl alcohol)) to protein modification. Comparison to earlier studies with active-site mutants of LADH implicates a role for proximal, but not distal, side chains in the modulation of hydrogen tunneling for this enzyme.
Estimation of Pavement Macrotexture by Principal Component Analysis of Acoustic Measurements

AbstractA method is developed to estimate the mean texture depth (MTD) value, which to some extent represents pavement quality, using measurements from a microphone mounted underneath a moving vehicle. Such measurements will include tire-generated sound that carries information about the road macrotexture as well as noise generated by the wind and vehicle. The proposed method uses principal component analysis (PCA) to differentiate important information about the road surface from noisy data while the vehicle is moving. The variations in frequency of the noise are assumed to be small compared with the variations in frequency of the signal related to the road-surface condition, which allows the PCA approach to separate noise from signals that carry information about the road-surface condition. The analysis begins with acoustic pressure measurements being made over various road-surface conditions underneath a moving vehicle. Fourier transforms are taken over various time windows and a PCA is performed over ...
A Comparison of Eleven Static Heuristics for Mapping a Class of Independent Tasks onto Heterogeneous Distributed Computing Systems

Mixed-machine heterogeneous computing (HC) environments utilize a distributed suite of different high-performance machines, interconnected with high-speed links, to perform different computationally intensive applications that have diverse computational requirements. HC environments are well suited to meet the computational demands of large, diverse groups of tasks. The problem of optimally mapping (defined as matching and scheduling) these tasks onto the machines of a distributed HC environment has been shown, in general, to be NP-complete, requiring the development of heuristic techniques. Selecting the best heuristic to use in a given environment, however, remains a difficult problem, because comparisons are often clouded by different underlying assumptions in the original study of each heuristic. Therefore, a collection of 11 heuristics from the literature has been selected, adapted, implemented, and analyzed under one set of common assumptions. It is assumed that the heuristics derive a mapping statically (i.e., off-line). It is also assumed that a metatask (i.e., a set of independent, noncommunicating tasks) is being mapped and that the goal is to minimize the total execution time of the metatask. The 11 heuristics examined are Opportunistic Load Balancing, Minimum Execution Time, Minimum Completion Time, Min?min, Max?min, Duplex, Genetic Algorithm, Simulated Annealing, Genetic Simulated Annealing, Tabu, and A*. This study provides one even basis for comparison and insights into circumstances where one technique will out-perform another. The evaluation procedure is specified, the heuristics are defined, and then comparison results are discussed. It is shown that for the cases studied here, the relatively simple Min?min heuristic performs well in comparison to the other techniques.