cssi/SciSciGPT-SciSciNet huggingface dataset:
SU‐FF‐T‐233: Commissioning and Quality Assurance of VMAT with An Ion Chamber Profiler

Purpose: To develop efficient and quantitative commissioning and quality assurance (QA) procedures for volumetric modulated arc therapy (VMAT) with an ion chamber profiler. Method and Materials: Rotational treatment techniques such as VMAT utilize variable dose rate, gantry speed and dynamic MLC to achieve optimal dose distribution. We designed QA test procedures to check machine output and beam characteristics variation with variable dose rate and gantry speed. MLC leaf positioning accuracy and leaf speed control were also checked. A linear ion chamber profiler was rigidly attached to the gantry head for all measurements. The profiler measured 4 profiles simultaneously: x‐axis, y‐axis and two diagonal lines. Dose rate was changed with fixed gantry or during arc rotation. Gantry speed was changed by varying the dose rate for the same arc beam delivery. To test MLC movement, MLC openings decreased from 32×32 cm2 to 4×4 cm2 during 90° arc rotation. The arc beam was repeated with same dose rate but different total MU, thereby changing the leaf speed. In each test, machine output and beam characteristics (flatness, symmetry and field width) were evaluated. Results: Beam remained stable except at very low dose rate (32 MU/min). Output varied from −1.6% to 2.4% at different gantry angles and dose rates. In gantry rotation speed test, gantry speed varies from 0.26 to 8.32 degree/sec. Beam was stable with maximum output change of 0.43%. In MLC leaf test, the difference between measured and expected leaf positions were within 1 mm for all the leaf speeds tested. Conclusion: The ion chamber profiler is an efficient and convenient tool for quantifying mechanical and dosimetric accuracy for rotational therapy. VMAT machine beam and output are generally stable with variable dose rate and gantry speed. Variations were observed at very low dose rate. MLC leaf positioning accuracy was within tolerance.
Targeted nanosensor aided three-dimensional pH mapping in tumor spheroids using two-photon microscopy

Tumors are generally characterized by a pH lower than the surrounding tissues. The mapping of tumor pH is of great importance as it plays a critical role in drug delivery and its effectiveness. Here we present a pH mapping technique in tumor spheroids, using targeted, ratiometric, fluorescent, pH nano-sensor that is based on two-photon excitation. Spheroids are micro-tumors that are widely used as an in-vitro three dimensional tumor model to study the different properties of the tumor for the purpose of drug delivery, therapy etc. The nanosensor consists of 8-Hydroxypyrene- 1,3,6-trisulfonic acid (HPTS), a pH sensitive dye, encapsulated in polyacrylamide hydrogel nanoparticle matrix and F3 peptide, conjugated to the nanoparticle's surface. The nanosensor has an average size of 68nm and contains approximately 0.5% dye by weight. The fluorescence intensity ratio, at the two-photon excitation wavelengths of 900nm and 750nm, increases linearly in the pH range from 6.0 to 8.0 and is used to determine the pH of the local environment. Our study reveals the pH distribution inside human cervix cancer spheroids (of different sizes) during the various stages of their formation. This information can be used to develop more efficient drug delivery mechanisms. The two-photon excitation used for this purpose is especially useful as it drastically minimizes both photobleaching and autofluorescence, thus leading to an increase in the signal-to-noise ratio. It also enables deep tissue imaging due to higher photon penetration depth.
On the c-axis conductivity and superconductivity of YBa2Cu3Ox as function of x

Abstract A theory is presented of the static c -axis conductivity and superconductivity of the YBCO state with varying oxygen concentration. The basis of the theory is the assumption that the hopping of electrons between the Cu0 2 planes is due to resonant tunneling through localized centers between the planes, and the amplitudes for different centers with the same energy are coherent. The dependence of the normal conductivity on temperature and concentrations of the resonant centers is calculated. Comparison with recent systematic determinations of the temperature-dependent conductivity at different oxygen concentrations shows reasonable agreement. From the obtained dependence of the concentration of resonant centers on the oxygen concentration it can be concluded that these centers disappear simultaneously with holes in the valence band, and hence both originate from the same impurity states with energies below the top of the valence band, which disappear at a certain doping. The supercurrent in the superconducting state proves to be of the Josephson type. The critical value is defined as a function of temperature and concentration of resonant centers. Its magnitude is estimated to be J c ∼ 10 5 −10 7 A/cm 2 .
A History of Music Education in the Black Community of Kansas City, Kansas, 1905-1954:

This study investigated music education in the black community of Kansas City, Kansas, from 1905 to 1954. It examined the facilities, teachers, curriculum, activities, and students to determine if this history was worthy of recognition by mainstream music education. Public documents, including annual reports, courses of study, personnel records, grade reports, programs, and newspaper articles, were the main sources of information. Interviews and letters of former students, teachers, and administrators were used as supportive evidence. The study documents the respectable music education that developed in this black community by identifying the black music educators who possessed outstanding credentials, the curriculum, and the musical activities that resulted from their students' involvement. This study, which helps to fill a void in the documentation of blacks in music education, provides valuable historical data on a nonwhite group's music educational development.
Coherent transients theorem: A comment

Schenzle, Wong, and Brewer have recently proposed a theorem [Phys. Rev. A 22, 635 (1980)] which states that the coherent transient signals produced in an optically thin gaseous sample of atoms are limited to a certain time interval after the excitation process which produces them. We comment on the range of validity of this theorem.
Epitaxial graphene RF field-effect transistors

The newly discovered electronic material graphene has attracted a lot of attention in the research community over the last few years because of its unique electronic properties. [1] It exhibits the highest carrier (electron or hole) mobility of >100,000 cm2/Vs at room temperature [2], which is about 10 times greater than that of state-of-the-art latticed-matched InP semiconductors, the current material of choice for high-speed RF applications. The saturation velocity (Vsat) of graphene is expected to be 2 to 4 times faster than that of lattice-matched InP HEMTs. [3] In addition, a potential combination of high current-carrying density, transconductance and low access resistance per input gate capacitance could make graphene an attractive candidate for high-speed RF operation.
The diagnosis of Cushing's syndrome

Spontaneous Cushing’s syndrome is well known but unusual clinical disorder. Many of the clinical features (central weight gain, glucose intolerance, hypertension, muscle weakness) are seen in other common conditions. Recognition of patients with multiple features, features unusual for their age (i.e. early onset osteoporosis or hypertension), patients with features more specific to Cushing’s syndrome (i.e. easy bruising, facial plethora, and violaceous striae), and patients with incidental adrenal mass or polycystic ovary syndrome should prompt an evaluation for cortisol excess. Late-night salivary cortisol, 1 mg overnight dexamethasone suppression testing, or 24 h urine free cortisol determination have excellent diagnostic characteristics and should be obtain in patients with suspected Cushing’ syndrome. If this initial testing is abnormal, further evaluation should be directed by an endocrinologist experienced in the diagnosis and differential diagnosis of Cushing’ syndrome.
A new technique for the determination of superficial residual stresses associated with machining and other manufacturing processes

Abstract Manufacturing processes induce residual stresses in components. The manufacturing operations path that a component has to undertake is critical in the formation of these residual stresses, as a change in processing order can change the residual stress profile of the component. There are many techniques available to both industry and researchers to measure these residual stresses. However, some of these techniques require either expensive equipment, highly trained operators or both. Other techniques require that holes be drilled into the component thus rendering the component useless. This paper introduces a new technique to measure superficial residual stresses, through the use of simple, easily available equipment. The technique involves the measurement of the change in spacing of pairs of hardness indents, which occurs upon relief of residual stress. The motivation for this paper was the exploitation of the potential advantages that high speed machining (HSM) offers to industry with regard to induced residual stresses. The new technique was developed by the authors to allow for confirmation of previously published results pertaining to the effects of HSM on such stresses and subsequently product life.
Prenatally injected testosterone propionate and sexual behavior of female rats

Abstract Female rats were exposed to oil or to testosterone propionate (TP) on Day 16 or Day 19 of gestation via injection into pregnant females. On Day 1 or Day 5 after birth, subgroups of these animals were injected with oil or TP. In adulthood, the external genital morphology, functional state of ovaries, and the display of feminine and masculine sexual behavior in response to exogenous hormones were examined. A high percentage of females exposed to TP on Day 19 of gestation had modified vaginas whereas other prenatally treated groups had normal genitalia. Prenatal treatment with TP alone did not appear to disrupt ovarian function since corpora lutea (CL) were present at approximately four months of age. However, injection of 1 μg TP on Days 1 or 5 postnatally did prevent the formation of CL across all prenatal treatment groups. Females exposed to TP on Day 19 of gestation exhibited deficits in feminine sexual behavior when compared to controls or females exposed to TP on Day 16 of gestation. The data support the concept of a discrete prenatal period during which circulating androgen influences the development of tissues which mediate feminine sexual behavior in the rat.
SU-E-T-377: Evaluation of Calculated and Measured HDR Brachytherapy Doses in the Presence of Heterogeneities

Purpose: With the recent introduction of the Grid‐Based Boltzmann Solver (GBBS) in commercial HDR brachytherapytreatment planning (Acuros™, Varian), there is now a rapid and accurate alternative to Monte Carlo calculations to attain improved dosimetric accuracy. The validation of Acuros™ has been performed by comparison to Monte Carlo calculations in water phantom. In this investigation, we compare calculated and measured doses in the presence of both high and low density heterogeneities. Methods: Phantoms were created incorporating both low and high density heterogeneities including representative densities of bone and air cavities. For the comparisons HDR plans were developed to deliver 100 cGy with TG‐43 formalism to optically stimulated luminescence(OSL)detectors placed in or near the heterogeneities. The detectors were calibrated by exposure to a known dose. The plans were then recalculated using the Acuros™ algorithm, and the dose to the detectors was determined both by calculation and measurement. Results: The OSLdetectors measured an average dose of 105 cGy when placed after a low density insert in the phantom, as compared to a calculated average dose of 107 cGy. When the OSLdetectors were placed after three different higher density inserts ranging from 1.3 to 1.9 g/cm3, the measured doses were 78, 77, and 75 cGy, compared to the calculated doses of 84, 82, and 75 cGy. Conclusions: The Acuros™ algorithm has been demonstrated to perform rapid and accurate dosimetry in homogenous water phantom. In this study we demonstrate that it performs accurately in the vicinity of heterogeneities expected to be encountered in the clinic. This work shows good qualitative agreement between measured and calculated high dose rate brachytherapydoses in the presence of both low and high density heterogeneities, and shows that the confidence‐building step of comparing calculated to measured dose can be readily made with simple phantom geometries.
Diffuse intracluster light in 10 clusters at 0.05 < z < 0.31

Surface brightness measurements of the diffuse intracluster light (ICL) in centrally concentrated, relaxed clusters have demonstrated that stars bound only to the cluster potential can contain anywhere from 5 to 50% of the total cluster flux. These stars are a by-product of the evolution of galaxies in clusters, and can be used to constrain models for the structure and evolution of clusters and their member galaxies. The ICL will be an important test of cosmological models as it is a baryonic component of clusters that is likely to evolve with redshift. To learn about these processes we are undertaking a program to measure the characteristics of the ICL (total flux, color, and substructure) as a function of cluster mass, morphology, and redshift. We have obtained data for a sample of 10 clusters at low and moderate redshifts. We discuss here our preliminary results for one cluster in that sample, A3888. With 4-5 hour integration times on-source per filter (V & gunn-r), we reach a 1 sigma surface brightness limit of 29.9 mag/arcsec $^{2}$ in the V band. We have identified an intracluster light component that is $\sim10\%$ of total cluster light, extends to 600 kpc from the center of the cluster, and is redder in color than the cluster galaxies ( $V-r = 0.4$ near the center, increasing to $V-r = 0.8$ at r = 500 kpc). In addition we find 3 low surface brightness features which are blue ( $V-r \simeq 0$ ), and in total are equivalent to one $m_V = 20.8$ mag galaxy. To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
Behavioral sensitization to cocaine after a brief social defeat stress: c-fos expression in the PAG.

The experiments explored the nature and time course of changes in behavior and Fos expression in the periaqueductal grey area (PAG) in response to an injection of cocaine that was given following a single episode of social defeat stress. Social defeat stress was defined as an intruder mouse’s response to an aggressive resident mouse. First, the intruder was briefly attacked, and secondly, it was threatened while protected by a perforated cage for 20 min. Plasma corticosterone levels rose after the beginning of the confrontation and remained elevated during the protected phase. In a first experiment, separate groups of intruder and control mice were challenged once with cocaine (20, 30, or 40 mg/kg) or saline. During tests for motor activity, behavioral measurements were obtained via (1) photobeam interruptions, (2) tracking of movements via image analysis, and (3) quantitative ethological analysis of postures and acts via videorecords. Several indices of ambulatory or horizontal forward locomotion confirmed the stimulant effects of cocaine. In a further experiment, separate groups of mice were challenged with 40 mg/kg cocaine at one time point, either during the social stress or 3, 5, 7 or 9 days thereafter. A cocaine challenge significantly increased locomotion 5 and 7 days after a brief social defeat stress, in excess of the level that is seen in non-stressed animals. Further experiments used immunohistochemical assays of sections through the caudal ventrolateral PAG and showed a significant increase in Fos-like immunoreactivity (Fos-LI) 1 h after the social stress experience or after cocaine. Importantly, concurrent administration of cocaine with social defeat stress produced inhibition of Fos expression throughout the PAG. A partial to complete recovery of cocaine-induced Fos expression was observed 5–7 days after social defeat stress. The results suggest that a single social stress episode is sufficient to engender a delayed sensitization of stimulant hyperactivity. The initial inhibition of Fos expression by concurrent social stress and cocaine may point to a relevant initiating event in the process of sensitization to stimulants.
Factors That Allow Polyolefins To Form Miscible Blends: Polyisobutylene and Head-to-Head Polypropylene

Solid-state CODEX NMR experiments directly probe chain dynamics in pure polyisobutylene (PIB), head-to-head polypropylene (hhPP), and their binary blend. The conclusions we draw from the results of the CODEX experiments, which are conducted over a temperature range of 210−300 K and which probe frequencies of 5−10 Hz, indicate that the overall chain dynamics of the blend system exceeds that of the two unmixed polymers. This is in agreement with our previous work on miscible PIB/polyethylene-co-butene blends [Macromolecules 2003, 36, 4844−4850], in which configurational entropy was shown to increase for miscible polyolefins. The CODEX experiments on PIB/hhPP, which offer the advantage of direct and simultaneous observation of both chains in the blend, show that conformational reorientation in hhPP increases significantly upon blending with PIB, while PIB chain dynamics are relatively unchanged. Rotating frame spin−lattice relaxation experiments support this conclusion. The benefits of direct chain observati...
The structure and use of a test generating system designed to facilitate individually paced instruction

The structure and use of a test-generating system having the following parameters is described.1. Each test is a ten item multiple choice instrument where each item has five (5) alternatives.2. Each test is generated from a relatively small file (most often less than 150 card images).3. Although the file contains only five (5) disjoint tests, over nine million different tests (each with its own set of correct answers) can be generated from it.4. The correct answers to each test are stored directly on the test (in coded form).5. Test responses are machine correctable and such correcting need not be done on the system that generated the test.6. The reliability of different forms of tests generated from one file is theoretically high (no statistical evidence is available to support a claim of high reliability).7. The grading program produces a total score as well as giving the correct answers for all items on that test.
Malthus, gender and the demarcation of ‘dangerous’ bodies in 1996 US welfare reform

This article argues that populationism as a gendered narrative provides a crucial rhetorical architecture for welfare reform debates in the USA during the 1990s. Populationism, which Joni Seager defines as ‘the dogma and the rhetoric of population alarmism and population control,’ subtly legitimized efforts to control and marginalize poor women's bodies in the context of welfare reform. The populationism underlying welfare reform hinges on a deep fear of engulfing social chaos if ‘we’ do not check the fertility of poor women, and particularly women of color. This article historically situates contemporary welfare politics by tracing in some detail how Malthus' original writings on population were constitutively linked to debates about ‘poor relief’ in early nineteenth century England. Exploring the gendered linkages between Malthus and social welfare policy in the 1800s allows us to understand how Malthus continues to haunt discourses about social welfare in the 1990s and beyond, with direct consequences ...
Single crystalline metal oxide nano-wires/tubes: controlled growth for sensitive gas sensor devices

Interest in quasi ID nanostructures of semiconducting oxides is exponentially grown in the last years, due to their attracting potential applications in electronic, optical and sensor field. After comparing the characteristics of several MOX nanowires recently published we discussed on the sensing properties of metal oxide nanowires and nanotubes, as conductometric and optical gas sensors, prepared by the authors. Single crystal nanostructures were synthesized with the aim of exploring and studying their capabilities as nanosized sensors in form of multi and single nanowire sensors.
Convergence in spelling, and spell-checker for Romanized Bangla in computers and mobile phones

Methods for Romanizing Bangla, or writing Bangla with the English alphabet were proposed half a century ago, but never gained popularity. Today, a new type of Romanized Bangla has emerged in mobile phone SMS, email, chatrooms, social networking websites, etc. Mobile phone SMS are widely used by individual users, phone operators, advertisers, the government, etc. In this study, about 500 – 1500 high-impact Romanized Bangla messages sent to wide audiences over about 4 years, were studied. In 2011 about 50% of Romanized Bangla words had converged to common and uniform spellings. In this study, the convergence to uniform spellings was seen to have increased to about 75 % of the words. Extrapolating from these trends, over the next three years, the convergence may rise to 85–90 % of words. Romanized spellings were found to be brief, for ease of typing with hand-held devices. English words were being rapidly absorbed into the Bangla language. As spellings converge further towards uniformity in the next few years. Romanized Bangla will become even easier to read and write, The common spellings also make it easier for computer softwares to recognize and convert Romanized Bangla to Bangla script. While it may not be possible or advisable to alter the convergence in the spelling trends, it may be possible to exert some force on the convergence with a spellchecker. Favorable spelling trends would make the Romanization consistent with pronunciations in English, making Bangla language more readily accessible by speakers of English.
Crystal structure of protein isoaspartyl methyltransferase: a catalyst for protein repair.

Abstract Background: Formation of isoaspartyl residues is one of several processes that damage proteins as they age. Protein L-isoaspartate (D-aspartate) O-methyltransferase (PIMT) is a conserved and nearly ubiquitous enzyme that catalyzes the repair of proteins damaged by isoaspartyl formation. Results: We have determined the first structure of a PIMT from crystals of the T. maritima enzyme complexed to S-adenosyl-L-homocysteine (AdoHcy) and refined it to 1.8 A resolution. Although PIMT forms one structural unit, the protein can be divided functionally into three subdomains. The central subdomain closely resembles other S-adenosyl-L-methionine-dependent methyltransferases but bears a striking alteration of topological connectivity, which is not shared by any other member of this family. Rather than arranged as a mixed β sheet with topology 6↑7↓5↑4↑1↑2↑3↑, the central sheet of PIMT is reorganized to 7↑6↓5↑4↑1↑2↑3↑. AdoHcy is largely buried between the N-terminal and central subdomains by a conserved and largely hydrophobic loop on one rim of the binding cleft, and a conserved Ser/Thr-rich β strand on the other. The Ser/Thr-rich strand may provide hydrogen bonds for specific interactions with isoaspartyl substrates. The side chain of Ile-206, a conserved residue, crosses the cleft, restricting access to the donor methyl group to a deep well, the putative isoaspartyl methyl acceptor site. Conclusions: The structure of PIMT reveals a unique modification of the methyltransferase fold along with a site for specific recognition of isoaspartyl substrates. The sequence conservation among PIMTs suggests that the current structure should prove a reliable model for understanding the repair of isoaspartyl damage in all organisms.
Effects of test solutes on the characterization of stationary phases in gas chromatography using a Snyder triangle

The effect of the choice of test solutes on the location of a stationary phase in the Snyder selectivity triangle was examined. The properties of proton-donating ability, proton-accepting ability and polarity were estimated using ethanol, dioxane and nitromethane, respectively. Significant changes in the selectivity, e.g., the locations of stationary phases in the triangle, were observed when the solute probes were changed by substituting homologues of ethanol for ethanol. However, modifying the calculation of selectivity so as to obtain a normalized value served to restore a phase to its original position in the selectivity triangle. This resulted in two corners of the triangle not having a representative phase. This study also confirmed the earlier report that additional liquid phases are needed because of the absence of phases in two of the three corners of the selectivity triangle.
A Mid-Latitude Space Weather Hazard Driven Directly by the Magnetosphere

Abstract This study revisits and attempts to quantify the effects of high-latitude electric field penetration on the mid-latitude ionosphere. These penetration electric fields (PEFs) are strongest during geomagnetically dynamic and disturbed conditions. The consequences of PEFs arise principally from the induced vertical drift of the F-layer from the eastward electric field component. Both positive and negative storm phases are associated with the PEF. Although no readily available description of the PEF exists, observational and modeling results are combined to provide a crude model. The largest uncertainty arises from a lack of knowledge of whether PEFs are always short lived (less than 1 h ) or are a persisting feature of disturbed conditions. According to simulations with the Utah State University time dependent ionospheric model (TDIM), under K p =3 conditions the PEF readily generates a factor of 2 increase in the pre-midnight ionosphere F-layer density (positive storm phase). For K p =5 conditions this positive phase is further enhanced to produce almost an order of magnitude increase in F-region density. Negative storm phases, F-layer density decreases, are also present in the pre-dawn and pre-noon sectors. The pre-dawn negative storm phase can reach a factor of 10 for K p =5 conditions while the pre-noon depletions are a few 10s of percent. These large density changes have operational impact on systems using coordinate registration based upon Global Positioning Satellite (GPS) measurements. GPS satellite-to-ground radio paths pass through the ionosphere at different angles relative to the zenith and hence have different propagation corrections dependent upon the paths total ionospheric electron content. Factors of 2 change in electron density corresponds to tens of centimeters to meters correction errors in coordinate registration position finding. Corrections this large are a potentially insurmountable obstacle for the GPS based wide area augmentation system (WAAS) designed to provide the airline industry over the USA position accuracy of only a few centimeters. Examples of mid-latitude ray tracing at 5 and 9 MHz are used to demonstrate the frequency sensitivity and coordinate registration dependence upon these factors of 2 ionospheric density changes. Operational systems such as the over-the-horizon (OTH) radar is very sensitive to such dependences and hence upon the mid-latitude PEF.
The impact of race on the development of severe heterotopic ossification following acetabular fracture surgery.

Abstract Objectives To determine the association between race on severe heterotopic ossification (HO) following acetabular fracture surgery. Design Retrospective case control study. Setting Level I university trauma centre. Methods Two hundred and fifty-three patients who were surgically treated for acetabular fractures were retrospectively evaluated. Postoperative radiographs were evaluated for HO by a blinded musculoskeletal radiologist, and classified based on a modified Brooker classification. Results Of the 253 patients that met inclusion and exclusion criteria, 175 (69%) were male and 78 (31%) were female. One hundred and fifty-four (61%) patients were Caucasian, and 99 (39%) were African American (AA). Fifty-five (21%) patients developed severe HO. Of those who developed severe HO, 25 were Caucasian (45%), 30 were African American (55%). Forty-one patients (75%) with severe HO were male, and 14 (25%) were female. No statistical differences (p > 0.05) were found between groups in terms of age, days to surgery, GCS at presentation, surgical approach, perioperative HO prophylaxis, or AO/OTA fracture classification. The patient population was then stratified by race, gender, and race/gender. AA were more likely than Caucasians to develop severe HO (odds ratio [OR], 2.24; confidence interval [CI], 1.22–4.11). When gender was considered independent of race, no statistical differences (p > 0.05) were observed (OR, 1.40; CI, 0.71–2.75). AA males were much more likely to develop severe HO when compared to Caucasian females (OR, 4.4; CI, 1.38–14.06). Conclusion Race is associated with different rates of severe HO formation following acetabular fracture surgery. AA patients are significantly more likely to develop severe HO following acetabular fracture surgery when compared to Caucasian patients.
Building Entrepreneurship in Subsistence Markets: Microfranchising as an Employment Incubator

Abstract Scholars indicate significant interest in business models that support entrepreneurial behavior in developing markets [Wankel C., editor. Alleviating Poverty through Business Strategy. New York: Palgrave Macmillan 2008]—particularly as they relate to job creation. This research introduces microfranchising as a business model adaptation that helps low-income individuals overcome non credit-related barriers to entry in obtaining employment. This study reveals a clear challenge for researchers—to better understand microfranchising and the extent to which the practice creates employment and enables individual business success. Largely unanswered questions concern the profiles of typical microfranchisees as well as the impacts of microfranchising on low-income individuals in subsistence marketplaces. This preliminary research focuses on one type of microfranchise operating in Accra, Ghana. Using data from microfranchises enables the exploration of whether workers in subsistence markets benefit from the microfranchise model. In comparing a microfranchise business with comparably-sized non-franchised businesses, this analysis finds preliminary evidence that the microfranchise creates starter jobs. Baseline results highlight microfranchisee characteristics and indicate that this form of microfranchising positively impacts savings and profits.
Nitrogen-15 Labeling of Dairy Feces and Urine for Nutrient Cycling Studies

Estimates of the availability of dairy manure nutrients to crops rely on indirect measurements and can vary greatly. More accurate estimates of manure nutrient availability are needed to improve manure management. The objective of this study was to enrich dairy feces and urine in 15 N to study nutrient flow in the feed-animal-manure-soil and crop-environment continuum. Ammonium sulfate (12.3 or 10 atom % 15 N) was applied to soil to enrich alfalfa (Medicago sativa L.) and corn (Zea mays L.) plants during growth. Alfalfa hay contained from 2.386 to 3.980 atom % 15 N in three harvests and corn silage contained 8.162 atom % 15 N. A feed mixture containing 55% alfalfa hay and 45% corn silage (4.026 atom % 15 N) was fed to two mature nonlactating cows (Bos taurus) for 36 h. The pattern of 15 N excretion in urine and feces was similar for both cows. The 15 N appeared in urine by 8 h and in feces by 24 h, and peaked by 30 h in urine (1.642 atom % 15 N) and by 54 h in feces (2.341 atom % 15 N). Enrichment approached basal levels at 132 h after initial feeding for both urine and feces. Of the total 15 N fed, 60% was recovered: 31% from urine and 29% from feces. Approximately 60 to 70% of the total N excreted in dairy feces was endogenous N and 30 to 40% was undigested feed N. Combining feces excreted during the 16- to 122-h period after initial feeding of 15 N-enriched feed would produce feces having uniformly labeled N components. The various 15 N-enrichment levels of urine and feces collected during different times after feeding offer possibilities for studying differential 15 N use in short-and long-term nutrient cycling studies.
Expected Revenue from Open and Sealed Bid Auctions

In his preceding piece, Paul Milgrom has neatly laid out many of the core results of the recent literature on the theory of competitive bidding. My immediate goal here is to provide the simplest possible derivation of three basic revenue ranking theorems. Each of these compares the expected revenue obtained from open bidding, as in the typical art auction, with the expected revenue obtained when bids are sealed and the winner pays his bid. The first of the ranking theorems is the revenue equivalence theorem which establishes conditions under which these two seemingly very different auctions generate the same expected revenue for the seller. The other two theorems establish the effect of relaxing one of the key assumptions. When buyers are risk averse, the seller gains if buyers submit sealed bids and the winner pays his bid. On the other hand, if valuations of different buyers are positively correlated, rather than unrelated, the seller extracts more revenue in an open ascending bid auction. In reducing these theorems to their basic elements, my deeper goal is to provide the reader with a better intuitive understanding of the results.
Superior vena caval replacement--superiority of irradiated caval homografts over heparin-bonded prosthetic grafts.

Abstract Our studies suggest that the use of superior vena caval homografts preserved frozen and sterilized by ionizing radiation (electron beam) is suitable for superior vena caval replacement. The addition of large venous homografts preserved and sterilized by irradiation to the arterial and aortic-valve homograft banks now in use should enhance its potential and usefulness.
Medical Therapy for Differentiated Thyroid Carcinoma

While some of the studies with new therapeutic modalities are encouraging, all are in their early experimental phases. It is likely that better understanding of the molecular basis for differentiated thyroid carcinoma will lead to new therapy in the next decade.
Consensual and behavioral validity of a measure of adaptive individual differences dimensions in human motivation

Data from three sources—an initial self sample (N = 108) and a friend sample (N = 103) and relative sample (N = 103) recruited by self sample participants—were used to test the consensual and behavioral validity of new individual differences measures of 15 dimensions of motivation represented in the assessment of individual motives-questionnaire (AIM-Q). AIM-Q scores for all three samples converged and hypotheses of their predicted relationships with reports of the occurrence and frequency of a variety of behavior criteria of some importance were supported in most cases. These results support the utility of the AIM-Q as a new measure of motives in purposeful human behavior.
The dose-toxicity of chlorpyrifos and endosulfan insecticides on the house fly by topical, vapor, and spray treatments as estimated by gas chromatography.

Gas chromatography was used for chemical analysis of amounts of chlorpyrifos and endosulfan reaching Musca domestica L. by vapor and spray. The dose-toxicity data obtained by these methods of treatment were analyzed by the probit method. The LD50 values thus derived were compared with those of topical applications of known concentrations, LD50 values for chlorpyrifos, in ng/female fly, were: 43±6.5, 57±27, 35±7.5, and 46.8±10.5, for topical, spray, vapor, (Experiment 1), and vapor (Experiment 2) treatments, respectively. Experiments with endosulfan gave LD50 values of 167±20, 216±30, and 143±47 ng/female for topical, spray, and vapor applications, respectively. These LD50, values obtained from different methods of delivery were not statistically different based on the overlapping of their confidence limits. They show that the toxicity of externally administered chlorpyrifos and endosulfan is not significantly influenced by differences in external methods of delivery. If true for all insecticides then the optimum spray droplet size for any target insect can be calculated from physical parameters related to diffusion and impingement.
A surgeon with acquired immunodeficiency syndrome: A threat to patient safety? The case of William H. Behringer

A year ago, the New Jersey case of William H. Behringer, the surgeon with acquired immunodeficiency syndrome (AIDS), caused health experts to focus on health care workers infected with human immunodeficiency virus (HIV) and to call for new policies and guidelines to protect patients against infection. After a year of acrimonious debate over the proper approach to the issues discussed in Behringer, no consensus has emerged. The Centers for Disease Control has quietly abandoned its plan to ease its July 1991 guidelines that call for infected professionals to cease performing invasive procedures or disclose their conditions to their patients. It has now decided to let each state set its own rules and regulations in compliance with its guidelines, or risk financial penalties. The issues discussed in Behringer have remained controversial. This case provides an opportunity to identify reasonable actions that may ensure patient safety without inciting public fears, unduly restricting individual freedom, or violating human rights.
Euglena gracilis chloroplast ribosomal protein operon: a new chloroplast gene for ribosomal protein L5 and description of a novel organelle intron category designated group III.

Abstract We describe the structure (3840 bp) of a novel Euglena gracilis chloroplast ribosomal protein operon that encodes the five genes rpl16-rpl14-rpl5-rps8-rpl36. The gene organization resembles the spc and the 3'-end of the S10 ribosomal protein operons of E. coli. The rpl5 is a new chloroplast gene not previously reported for any chloroplast genome to date and also not described as a nuclear-encoded, chloroplast protein gene. The operon contains at least 7 introns. We present evidence from primer extension analysis of chloroplast RNA for the correct in vivo splicing of five of the introns. Two of the introns within the rps8 gene flank an 8 bp exon, the smallest exon yet characterized in a chloroplast gene. Three introns resemble the classical group II introns of organelle genomes. The remaining 4 introns appear to be unique to the Euglena chloroplast DNA. They are uniform in size (95-109 nt), share common features with each other and are distinct from both group I and group II introns. We designate this new intron category as 'group III'.
Got jobs? [Point of View]

Discusses the lack of employment opportunities for U.S. engineers as many jobs have been offshored and new jobs are scarce.
Consequences of injuries on survival and reproduction of common bottlenose dolphins (Tursiops truncatus) along the west coast of Florida

Accurate identification of human-induced injuries that lead to death or interfere with reproduction is important for marine mammal management, as deaths exceeding established limits can lead to restrictions on fisheries or vessel operations. The fates of cetaceans last seen swimming with attached gear, particularly in pelagic fisheries, or with vessel strike lacerations, have been difficult to predict. Survival and reproduction data from long-term research on resident common bottlenose dolphins near Sarasota, Florida were examined relative to consequences of fishing gear ingestion, line entanglements, vessel strikes, and amputations of unknown origins. Fishing hooks embedded in the throat, goosebeak, or esophagus, or line wrapped around the goosebeak, generally lead to death. Multiple, constrictive line wraps around fin insertions can lead to amputation, blood loss, impaired mobility, or infection. Dolphins with ingested gear or severe entanglements may swim away with the gear, but likely die later. Propeller injuries involving only soft tissue were often survivable. Some dolphins survived amputations of the distal ends of fins, and continued to reproduce. As a precautionary approach, dolphins with ingested gear or severe constrictive entanglements should be considered mortalities, but extrapolations of findings from coastal bottlenose dolphins to other cetaceans and different gear must be done with caution.
alpha-Lipoic acid prevents the development of glucose-induced insulin resistance in 3T3-L1 adipocytes and accelerates the decline in immunoreactive insulin during cell incubation.

Oxidative stress has been implicated in glucose toxicity. We tested the hypothesis that certain antioxidants may prevent insulin-resistant glucose transport that develops in adipocytes after sustained exposure to high glucose, provided insulin is present. The antioxidant alpha-lipoic acid has been proposed as an insulin sensitizer. 3T3-L1 adipocytes were preincubated 18 hours in media containing insulin (0.6 nmol/L) with low (5 mmol/L) or high (25 mmol/L) glucose with or without alpha-lipoate, dihydrolipoate (each 0.1 to 0.5 mmol/L), or N-acetylcysteine (1 to 5 mmol/L). After extensive re-equilibration in insulin and antioxidant-free media, basal and maximally insulin-stimulated (100 nmol/L) glucose transport was measured. Insulin was quantified by radioimmunoassay. Preincubation with alpha-lipoate and dihydrolipoate but not N-acetylcysteine increased subsequent basal glucose transport; the effect was much smaller than that of acute maximal insulin stimulation. Preincubation in high glucose without antioxidants inhibited acutely insulin-stimulated glucose transport by 40% to 50% compared with low glucose. This down- regulation was partially or completely prevented by each antioxidant. In cell-free media, the 2 reductants, dihydrolipoate and N-acetylcysteine, rapidly decreased immunoreactive insulin, but alpha-lipoate was ineffective. However, during incubation with adipocytes, alpha-lipoate, and dihydrolipoate promoted the decline in immunoreactive insulin nearly equally. Because insulin and high glucose are synergistic in inducing insulin resistance in this model, the reduction in immunoreactive insulin probably contributed to the protective effect of the antioxidants. 3T3-L1 adipocytes efficiently metabolize alpha-lipoate to dihydrolipoate, which may be released into the medium. The stimulation of glucose transport by alpha-lipoic acid may represent redox effects in subcellular compartments that are accessible to dihydrolipoate.
On the realizability of pair correlation functions

Abstract The pair correlation function g 2 ( r ) provides a basic geometric descriptor for many-particle systems. It must obey two necessary conditions: (i) non-negativity for all distances r, and (ii) non-negativity of its associated structure factor S ( k ) for all k. Here we utilize an improved stochastic construction algorithm for particle configurations to establish conditions in which (i) and (ii) are also sufficient, i.e., g 2 ( r ) is in fact realizable. Two types of target pair correlation functions have been investigated in one, two, and three dimensions for hard-core particles, specifically a unit step function, and a contact δ plus step pair correlation function. Results indicate that the former target function is realizable up to a terminal density set by necessary condition (ii), at which the particle core packing fraction equals 2 - d in d dimensions. Furthermore, results are consistent with the proposition that for d > 1 the contact δ plus step function is realizable up to a terminal density due to condition (ii) at which the packing fraction of cores is ( d + 2 ) / 2 d + 1 [Torquato and Stillinger, J. Phys. Chem. B 106 (2000) 8354, 11406].
Focus of attention and placebo utility

Abstract The effects of focus of attention and expected drug effects on reactions to a placebo were examined in two experiments. In the first experiment self-aware and non-self-aware subjects were given a placebo that was said to be either performance-facilitating or inhibiting and then they worked on a set of arithmetic problems. It was expected that the non-self-aware subjects, but not the self-aware subjects, would display a self-serving bias in their attributions regarding the effects of the placebo. Specifically, it was predicted that non-self-aware subjects would attribute more arousal to the performance-inhibiting drug than the performance-facilitating drug since such attributions would be more psychologically beneficial or “useful” in the sense that they would make actual performance on the task look more impressive. Consistent with these predictions, there was evidence of a self-serving bias in drug reactions only among the non-self-focused subjects. Those who were made self-aware did not respond differentially to the two types of drug information. Instead, they appeared to respond in line with their actual (aroused) internal states by attributing some arousal to both drugs. In the second experiment arousal was reduced by eliminating the task, and this time self-focused subjects again appeared to be more aware of their actual internal states, as they reported less reaction to the placebo, regardless of the effects ascribed to it. Two conclusions are drawn from these results: (a) perceived drug utility does effect placebo responsiveness, and (b) self-focused attention increases awareness of internal states, but not necessarily the causes of those states.
Control of territorial aggression in a changing environment

Abstract A sedentary population of song sparrows, Melospiza melodia morphna, in western Washington State shows year-round territoriality but in different contexts. During the breeding season (March–August), all defend multiple purpose territories as monogamous pairs, or alone, but only about 30% of individuals remain on the same territory during the nonbreeding season (September–February). During the breeding season, territorial behavior is tightly correlated with circulating levels of luteinizing hormone (LH) and testosterone, but identical behaviors during the nonbreeding season appear to be expressed independently of gonadal hormones. First summer males establish territories with basal plasma levels of LH and testosterone. Castrated male song sparrows defend territories equally well as intact males in autumn and continue to do so even through onset of the breeding season. It can therefore be questioned whether testosterone has any role in activation of territorial behavior in this species. Experiments in which testosterone levels were manipulated indicate that testosterone does not simply activate territorial behavior but enhances “persistence” of aggression during the breeding season. It is suggested that although territorial behavior may be expressed year-round, the context, neural, and hormonal bases of territoriality may change dramatically.