bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptation of a proton transfer reaction mass spectrometer instrument to employ NO+ as reagent ion for the detection of 1,3‐butadiene in the ambient atmosphere
Authors: Knighton W. B. , Fortner E. C. , Herndon S. C. , Wood E. C. , Miake‐Lye R. C.
Published: September 2009

A proton transfer reaction mass spectrometer (PTR‐MS) instrument was adapted to employ NO+ as a chemical reagent ion without any hardware changes by switching the reagent ion source gas from water vapor to dry air. Ionization of dry air within the hollow cathode ion source generates a very intense source of NO+ with only a minor impurity of NO. The intensities of the primary NO+ reagent ion and the unwanted impurity NO are controllable and dependent on the operational conditions of the hollow cathode ion source. Ion source tuning parameters are described, which maintain an intense source of NO+ while keeping the impurity NO signal to less than 2% of the total reagent ion intensity. This method is applied to the detection of 1,3‐butadiene. NO+ reacts efficiently with 1,3‐butadiene via a charge exchange reaction to produce only the molecular ion, which is detected at m/z 54. Detection sensitivities of the order of 45 pptv for a 1‐s measurement of 1,3‐butadiene are demonstrated. We present the first real‐time on‐line sub parts per billion measurement of 1,3‐butadiene in the ambient atmosphere. The only likely interference is from 1,2‐butadiene. Concurrent measurements of benzene are provided and suggest that the vehicular emissions are the predominant source of 1,3‐butadiene in a suburban Boston area monitoring location. Copyright © 2009 John Wiley & Sons, Ltd.
The very short frame of mobile DVB‐RCS: Code design and QoS Performance
Authors: Liva Gianluigi , Papaleo Marco , Párraga Niebla Cristina , Cioni Stefano , Scalise Sandro , Vanelli‐Coralli Alessandro , Corazza Giovanni E. , Kim Pansoo , Lee Ho‐Jin
Published: September 2009

In this paper, the design of a new very short frame introduced in the upcoming version of DVB‐RCS standard targeting interactive mobile services will be described. The frame design with a special focus on channel coding and performance are addressed in detail, as well as an evaluation of the QoS performance for realistic traffic scenarios, propagation channel conditions, and carrier sizes. Copyright © 2009 John Wiley & Sons, Ltd.
Harmonizing maturity levels from CMMI‐DEV and ISO/IEC 15504
Authors: Pino Francisco J. , Baldassarre Maria Teresa , Piattini Mario , Visaggio Giuseppe
Published: September 2009

ISO has recently published Part 7 of the ISO/IEC 15504 standard, with the aim of determining the extent to which an organization consistently implements processes that contribute to achievement of its business goals. This new Part 7 of ISO/IEC 15504 has addressed issues related to the assessment of organizational maturity, as the CMMI‐DEV model also does. Recently, growing interest has been shown towards the need to harmonize different improvement models or standards, thereby presenting an integrated vision about them. All this being so and in an effort to offer information on how the maturity levels described in these two models are related, we have carried out the harmonization of these two models. It is based, firstly, on a mapping between processes of ISO 12207:08 and process areas of CMMI‐DEV, and in second place, on a matching between processes of ISO 12207:08 and ISO 15504‐5. For this work, we have taken into account the latest versions of the models, and defined a suitable process to carry out the mapping in a systematic way. We established differences and similarities between the maturity levels (and their processes) described in these models, our goal being to support organizations which are interested in tackling organizational maturity. Copyright © 2009 John Wiley & Sons, Ltd.
Integrating ISO/IEC 15504 conformant process assessment and organizational reuse enhancement
Authors: Stallinger Fritz , Plösch Reinhold , Pomberger Gustav , Vollmar Jan
Published: September 2009

Improving reuse in industrial engineering is more and more recognized as a key to economic success by providers of industrial solutions. It generally increases the quality of the engineered systems, shortens engineering time, and decreases engineering costs for the development of customer‐specific industrial solutions. We therefore developed an integrated set of methods for assessing an organization's reuse practices, identifying its reuse potential and guiding the selection and implementation of improvement actions.

While the assessment of reuse practices is performed according to the principles of ISO/IEC 15504 for process assessment, identification of improvements for reuse in industrial engineering is much more complex compared to ‘traditional’ process capability‐oriented improvement. Orthogonal to improving along the process capability dimension it also involves strategic decisions on the overall design of the engineering process, the pursued engineering and reuse paradigms, the desired organizational reuse maturity stages, etc.

To tackle this problem, we developed a potentials analysis method that assures compliance of the improvements with the strategic goals of the organization. It bridges the gap between the process assessment and the improvement action planning parts of the methodology by supporting the selection of reuse practices considering strategic issues and business goals. Copyright © 2009 John Wiley & Sons, Ltd.
Bringing language to life in second‐year Spanish
Authors: Davis Debra Dimon
Published: September 2009

Concerned that her students “knew” Spanish but could not use it in real life situations, Davis created new learning goals, new learning activities, and new assessment activities. Result? New kinds of significant learning.
Inspiration and intellect: Significant learning in musical forms and analysis
Authors: Kelley Bruce C.
Published: September 2009

Fink's integrated course design provides a way to put hopeful theory into the reality of practice. The author describes how this model helped him use more active learning experiences that not only deepened students' understanding of musical forms but also enabled students to creatively play with those forms.
Using Fink's integrated course design: How a book changed our students' learning, our university, and ourselves
Authors: Fallahi Carolyn R. , Levine Laura E. , Nicoll‐Senft Joan M. , Tessier Jack T. , Watson Cheryl L. , Wood Rebecca M.
Published: September 2009

This chapter presents an interdisciplinary approach to course redesign that enhanced student learning across all six categories in Fink's taxonomy. A meta‐analysis of the results provides evidence that integrated course design produces significant learning.
Using integrated course design to build student communities of practice in a hybrid course
Authors: Fayne Harriet R.
Published: September 2009

A very experienced teacher faces the challenge of teaching a new course where students meet face‐to‐face only ten times.
An “extreme makeover” of a course in special education
Authors: Nicoll‐Senft Joan M.
Published: September 2009

Instead of tinkering with minor changes, the author used integrated course design as a blueprint for a major overhaul of her course.
Implementation and analysis of proxy MIPv6
Authors: Guan Jianfeng , Zhou Huachun , Yan Zhiwei , Qin Yajuan , Zhang Hongke
Published: September 2009

Mobile IPv6 (MIPv6) is a host‐based mobility support specification which has been approved by the IETF as the standardized solution of global mobility management in IPv6 network for Mobile Node (MN). However, MIPv6 handover procedure results in a large handover delay. To improve its performance, some MIPv6 variants such as Fast Handover for MIPv6 (FMIPv6) and Hierarchical MIPv6 (HMIPv6) were proposed. However, they all require the MN to support the mobility management protocols which increase the difficulty of management and deployment. Recently, IETF NETLMM workgroup published the Proxy Mobile IPv6 (PMIPv6) which is a network‐based localized mobility management to provide the mobility support for mobile host without the involvement of the mobility signaling. In this paper, we analyze the singling cost of PMIPv6 and implement it in our test‐bed to evaluate its performance. The results show that the PMIPv6 has lower signaling cost and packet delivery cost, and it can improve the handover performance of UDP and TCP than the other mobility management protocols under low‐delay networks, as for the wide area networks, it needs to introduce some mechanism like fast handover to further improve its performance. Copyright © 2009 John Wiley & Sons, Ltd.
Characteristics analysis and modeling of frame traffic in 802.11 wireless networks
Authors: Ge Xiao‐hu , Yang Yang , Wang Cheng‐Xiang , Liu Ying‐Zhuang , Liu Chuang , Xiang Lin
Published: September 2009

In this paper, we analyze the impacts of different frame types on the self‐similarity and burstiness characteristics of the aggregated frame traffic in a real 802.11 wireless local area network (WLAN). We find that the impacts of different frame types are related to the mean frame sizes and the proportions of specified frame types in the aggregated frame traffic. Furthermore, we propose an analytical model to capture the relationship of self‐similarity characteristics between the aggregated frame traffic and different frame types. These new results provide an insight of frame traffic characteristics and some practical guidelines for developing new efficient algorithms to improve the common medium utilization and system throughput performance. Copyright © 2009 John Wiley & Sons, Ltd.
Insertion of Methylthiirane into the P–I Bonds of α‐P4S3I2
Authors: Tattershall Bruce W. , Geneux Nicholas S. , Holmes Kathryn E. , Hargreaves Michael D. , McMorrow Glenn
Published: September 2009

Rac‐methylthiirane inserted into the P–I bonds of α‐P4S3I2, giving two diastereomers of exo,exo‐α‐P4S3(SCHMeCH2I)I and three diastereomers of exo,exo‐α‐P4S3(SCHMeCH2I)2, as kinetic products, identified by 31P and 13C NMR spectroscopy in the reaction solutions. Ab initio modelling, using the DF MPW1PW91 method, showed that corresponding products containing the SCH2CHIMe substituent should be more stable, but only α‐P4S3(SCHMeCH2I)(SCH2CHIMe) was suggested by the NMR evidence as a lower yield product. The initially formed thiolates were sulfurised by further methylthiirane on heating or in the presence of the sulfur transfer catalyst Re(O)Cl3(PPh3)2, to give low concentrations of α‐P4S3(S)(SCHMeCH2I)I and α‐P4S3(S)(SCHMeCH2I)2, in which a monocoordinate sulfur atom was attached to a phosphorus atom carrying the thiolate group. The number of diastereomers appropriate for only one orientation of the terminal sulfur relative to the cage skeleton was found in significant concentration in each case, in contrast to previous work on sulfurisation ofα‐P4S3 diamides.

Supporting information for this article is available on the WWW under http://www.wiley‐vch.de/contents/jc_2260/2009/index.htm or from the author.
Coordination Polymers Based on the 2,5‐Dihydroxyterephthalate Ion and Alkaline Earth Metal (Ca, Sr) and Manganese Cations
Authors: Dietzel Pascal C. , Blom Richard , Fjellvåg Helmer
Published: September 2009

Four novel coordination polymers were solvothermally synthesized from metal(II) salts (the metals being Mn, Ca, and Sr) and 2,5‐dihydroxyterephthalic acid (H4dhtp), and their crystal structures were determined by single‐crystal X‐ray diffraction analysis. Of the two different types of functional group of the organic linker, only the carboxylic acid has been deprotonated on formation of the compounds. The manganese compound Mn(H2dhtp)(H2O)2, CPO‐26‐Mn, contains octahedrally coordinated metal atoms in a three‐dimensional framework. It is isostructural with the previously reported magnesium compound CPO‐26‐Mg. The heavier alkaline earth elements calcium and strontrium exhibit higher coordination numbers in their compounds. Calcium was found to form two compounds depending on reaction conditions, Ca(H2dhtp)(H2O)2, CPO‐20, and Ca(H2dhtp), CPO‐21. Both structures consist of three‐dimensional networks. CPO‐20 contains dimeric edge‐sharing calcium coordination polyhedra, whereas in CPO‐21 the octacoordinate calcium coordination polyhedra are linked by common edges to straight one‐dimensional chains. The crystal structure of Sr(H2dhtp)(H2O), CPO‐22, is similar to that of CPO‐21. Again, the coordination polyhedra are condensed by shared edges into one‐dimensional chains. However, because the strontium atom is nonacoordinate, with the additional ligand being the water molecule, the chains are corrugated in this case.
Liver transplantation for hepatocellular carcinoma: the Japanese experience
Authors: Furukawa Hiroyuki , Shimamura Tsuyoshi , Suzuki Tomomi , Taniguchi Masahiko , Nakanishi Kazuaki , Yamashita Kenichiro , Kamiyama Toshiya , Matsushita Michiaki , Todo Satoru
Published: September 2009

Despite the wide spectrum of selection criteria used by living donor liver transplantation (LDLT) centers in Japan, LDLT for hepatocellular carcinoma (HCC) can achieve an acceptable outcome comparable to the outcome for deceased donor liver transplantation (DDLT) for HCC. One of the most crucial considerations in liver transplantation for HCC is the advent of expanded criteria that allow more patients with HCC to receive the organs and offer similar or even better results compared to the Milan of UCSF criteria. Expanded criteria for HCC are proposed from three single‐center and one multicenter study in Japan. These criteria are based on the independent predictors for outcome derived from the analyses of the pretransplant factors and explant pathology. The beneficial effect of those proposed criteria can be predicted by the inclusion rates of the patients compared to the Milan or UCSF criteria in the same cohort and the outcome for those included patients. While application of the UCSF criteria increases the inclusion rate compared to the Milan criteria by 5–10%, these proposed criteria increase the inclusion rates by 5–54% compared to the Milan criteria. The higher inclusion rates compared to the application of the Milan criteria are achieved by criteria including tumor markers, either AFP or PIVKA II or both. Inclusion of tumor markers in addition to parameters of tumor morphology might be the key to establish the best criteria for liver transplantation for HCC.
Hall Measurements on Carbon Nanotube Paper Modified With Electroless Deposited Platinum
Authors: Petrik Leslie , Ndungu Patrick , Iwuoha Emmanuel
Published: September 2009

Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt) distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed.
Phaeohyphomycotic osteomyelitis in the femur of a cat
Authors: Hess Michal O.
Published: September 2009

A 4-month-old castrated male domestic shorthair cat was presented for a right hind leg lameness of 1-week duration. Physical examination revealed a painful swelling over the right distal femur. A radiograph of the right stifle revealed an extensive lytic lesion involving the distal metaphysis of the right femur. Cytological examination of a needle aspirate was consistent with a deep fungal infection. A pigmented dimorphic fungus was isolated in pure culture from a representative needle aspirate from the lesion. The patient improved substantially after 5 weeks of high-dose itraconazole therapy, although it was subsequently lost to follow-up.
Modeling the Size of Wars: From Billiard Balls to Sandpiles
Authors: CEDERMAN LARS-ERIK
Published: September 2009

Richardson's finding that the severity of interstate wars is power law distributed belongs to the most striking empirical regularities in world politics. This is a regularity in search of a theory. Drawing on the principles of self-organized criticality, I propose an agent-based model of war and state formation that exhibits power-law regularities. The computational findings suggest that the scale-free behavior depends on a process of technological change that leads to contextually dependent, stochastic decisions to wage war. Early drafts of this paper were prepared for presentation at the University of Michigan, the University of Chicago, Ohio State University, Yale University, the University of Pennsylvania, and Cornell University. I am grateful to the participants in those meetings and to Robert Axelrod, Claudio Cioffi-Revilla, Fredrik Liljeros, and the editor and the anonymous reviewers of this journal for excellent comments. Laszlo Gulyas helped me reimplement the model in Java and Repast. Finally, I would like to acknowledge the generous support of the John M. Olin Institute for Strategic Studies. Nevertheless, I bear the full responsibility for any inaccuracies and omissions.
Interpreting Dragomans: Boundaries and Crossings in the Early Modern Mediterranean
Authors: Rothman E. Natalie
Published: September 2009

Early modern observers rarely failed to comment on the perceived diversity of peoples, customs, and languages of Mediterranean societies. This diversity they sought to capture in travel narratives, costume albums, missionary and diplomatic reports, bilingual dictionaries, and a range of other genres of the “contact zone.” Modern scholars, too, have celebrated the early modern Mediterranean's ostensibly multiple, diverse, and even “pluralist,” “cosmopolitan,” or “multicultural” nature. At the same time, in part thanks to the reawakened interest in Braudel's seminal work and in part as a much-needed corrective to the politically current but analytically bankrupt paradigm of “clash of civilizations,” recent studies have also emphasized the region's “shared,” “connected,” “mixed,” “fluid,” “syncretic,” or “hybrid” sociocultural practices. Of course, these two analytical emphases are far from mutually exclusive, as recently underscored by Peregrine Horden and Nicholas Purcell's comprehensive, longue durée model of diversity-in-connectivity. Yet, neither Horden and Purcell's structuralist “new thalassology,” nor other studies of the early modern Mediterranean have offered a systematic account of how “diversity” and “connectivity” as both the flow of social practices and the categories for speaking about them have been articulated through specific institutions and genres.
Sympathy for the Weary State?: Cold War Chronotopes and Moscow Others
Authors: Lemon Alaina
Published: September 2009

Julya paces the parquet, blond hair coiled severely, hands clasped atop padded buttocks encased in a boxy gray, ill-fitting suit. She sputters abuse at her audience: fifteen classmates sprawled on the floor, their teacher seated in a chair, and a video camera. Moscow, November 2002. The Americans prepare to invade Iraq, Putin serves his third year as president, and these students begin their first term at the Russian Academy for Theatrical Arts (RATI/GITIS). Inside its walls, Julya depicts the head of her high school, an older woman in a town two hours north. She yells: “I REQUEST that TODAY at the meeting with ZhshzhshshzhshuGAnov you ALL be there!” (Zjuganov is the leader of the Russian Communist Party.) Some students slap the parquet laughing. Their teacher is less impressed.
Memory, Mimesis, and Narrative in the K'iche' Mayan Serpent Dance of Joyabaj, Guatemala
Authors: Hutcheson Maury
Published: September 2009

It seemed to me a simple question. “What happens in this dance-drama? What is the storyline, the narrative?” I am met by puzzlement. The dancer explains that each such dance has its own set of instruments, its own special costumes and masks. For this one they use a simple, one-man marimba and the costumes come from the nearby town of Chichicastenango.
Africa and the Nuclear World: Labor, Occupational Health, and the Transnational Production of Uranium
Authors: Hecht Gabrielle
Published: September 2009

What is Africa's place in the nuclear world? In 1995, a U.S. government report on nuclear proliferation did not mark Gabon, Niger, or Namibia as having any “nuclear activities.” Yet these same nations accounted for over 25 percent of world uranium production that year, and helped fuel nuclear power plants in Europe, the United States, and Japan. Experts had long noted that workers in uranium mines were “exposed to higher amounts of internal radiation than … workers in any other segment of the nuclear energy industry.” What, then, does it mean for a workplace, a technology, or a nation to be “nuclear?” What is at stake in that label, and how do such stakes vary by time and place?
‘Heterosis’ in F1mice in a cold environment
Authors: Barnett S. A. , Coleman Elizabeth M.
Published: September 2009

The effect of hybridity on reproduction in mice has been studied in two environmental temperatures: 21° C. (‘normal’) and −3° C. (unfavourable). Mice of inbred strains A2G and C57BL are maintained as permanent breeding stocks in each of the two temperatures. In each temperature the two strains were crossed, and the reproduction of F1pairs, to the age of 28 weeks, compared with that of the parent strains.

At 21° C. the expected superior fertility of the F1mice was found: the number of litters produced was not affected, but there were more young produced per pair. The number of young per pair reared to 3 weeks was about twice the mean of the parent strains at the same temperature.

At −3° C. the difference was greater. The F1pairs produced more and larger litters than the parent strains, and deaths between birth and weaning at 3 weeks were few. The number of young per pair reared to 3 weeks was nearly five times the mean of the parent strains. Part of the superiority of the F1mice, at both temperatures, was due to the fact that they began to breed earlier.

Despite the larger litters produced by the F1pairs, at 21° C. the mean weight of the F2young at the age of 3 weeks was intermediate between those of the parent strains. At −3° C. it was the same as that of the heavier parent strain, namely, A2G.

As a further test of resistance to cold, F1mice born in the warm environment were transferred to the cold at the age of 22 days and there placed each alone in a cage, with nesting material. In these conditions they had a higher survival rate than the young of either of the parent strains. They also grew faster than the A2G mice.

The F1mice were not only more fertile than the inbred mice, but also more uniform in breeding performance. This difference was especially marked in the less favourable environment.

These observations are in conformity with the view that heterosis is a consequence of heterozygosis; and that it depends on an enhanced ability to withstand disturbances of developmental and physiological equilibria.
How pure are our inbred strains of mice?
Authors: Deol M. S. , Grüneberg H. , Searle A. G. , Truslove G. M.
Published: September 2009

Sixty-six individual tests on an array of skeletal variants showed an essential absence of parent-offspring correlations in the inbred strains C57BL, A and CBA in the mouse. It is concluded that these strains, and inbred strains of mice in general, are genetically homogeneous except for the differentiation of genetically distinct sublines as the result of mutations.
Mutation induced in germ cells of the foetal female mouse
Authors: Carter T. C.
Published: September 2009

In Great Britain by far the greater part of the genetically effective dose of man-made radiation to the human population is due to high-intensity irradiation of the gonads in medical radiology; about a third of it is received by post-natal males, a third by post-natal females, and a third by foetuses, mainly in the later stages of gestation (Osborn & Smith, 1956).
Selection of mice for growth on high and low planes of nutrition
Authors: Falconer D. S.
Published: September 2009

1. Two-way selection was applied to the growth of mice between 3 and 6 weeks of age when reared on a high plane of nutrition and, in another pair of lines, when reared on a low plane of nutrition. In each generation the growth of all four lines was measured on both high and low planes of nutrition.

2. Growth on the two planes of nutrition was treated as two different characters and the direct and correlated responses of each were estimated. The genetic correlation between the two characters was estimated from the responses of each of the four lines, and from the divergence between upward-and downward-selected lines. The different estimates should be the same if the theory of selection for correlated characters adequately accounts for the responses. Up to generation 7 the agreement was reasonably good, but in the later generations it was not. Four estimates of the genetic correlation up to generation 7 were: 0·75, 0·19, 0·66, 0·57.

3. There was asymmetry between the upward and downward responses, and the realized heritabilities changed over the course of the experiment; so also did the phenotypic variation. In all these respects the lines behaved differently.

4. The conclusions drawn from the final responses are summarized at the beginning of the Discussion.

5. The mice produced by selection for increased growth on low plane, but later reared on high plane, were compared with those produced by selection on high plane. Their growth was the same, but they were heavier, had less fat and more protein, and were better mothers.
Cytogenetic analysis of the action of carcinogens and tumour inhibitors in Drosophila melanogaster VI. The Mutagenic cell Stage Response of the Male Germ Line to the ‘Nitrogen-Mustard’ Derivatives of Amino-acids, Carboxylic acids and amines
Authors: Fahmy O. G. , Fahmy Myrtle J.
Published: September 2009

The analysis of the variation in the mutation rate in the fractionated progeny of treated males, revealed a marked differential cell stage response to the various chemical series investigated. The mustard derivatives of amino-acids (particularly L-phenylalanine) exert their minimal mutagenicity on mature sperm, but possess an appreciable activity on other stages of spermatogenesis, including spermatogonia. The carboxylic-acid mustards produce their maximal effect on an early spermatid, but are practically ineffective on spermatocytes and spermatogonia. The amine mustard corresponding to the phenylalanine derivative is effective on the stages of spermiogenesis (including the early spermatids) as well as on the spermatocytes, but is inactive on the spermatogonia (at least the primary stages). The response of the gonia, therefore, is a function of the amino-acid moeity of the mutagen, and is not merely due to the presence of an amino-group in the molecule.
Zigzag: a genetic defect of the horizontal canals in the mouse
Authors: Lyon Mary F.
Published: September 2009

The name zigzag has been given to an inherited behaviour defect in the mouse in which the animals walk with a zigzag motion. It is inherited polygenically. The anatomical defect responsible for the abnormal behaviour was a reduction or absence of the horizontal canals of the inner ear, the reduction consisting of a constriction in the middle of the canal length, rather than a shortening of the canal.
Genetical studies on the skeleton of the mouse XXV. The Development of Syndactylism
Authors: Grüneberg Hans
Published: September 2009

1. The earliest manifestations of the gene for syndactylism discovered include hyperplasia of the apical ectodermal ridge of the limbs and hyperplasia of parts of the limb epidermis (10–10½-day stage). Somewhat later, a similar hyperplasia of the epidermis in the distal parts of the tail is found in some sm/sm embryos.

2. Enlargement and deformation of the foot plates in both fore and hind limbs is present in the 12-day stage; in the fore limbs it probably starts on the preceding day. The foot plates are bent over in a palmar or plantar direction respectively; the crowding together of the middle digits thus produced is the mechanical cause of syndactylism.

3. It is suggested that the enlargement of the foot plates with the ensuing deformities is due to increased stimulation of mesenchymal growth by the hyperplastic apical ectodermal ridge. On this interpretation, all the skeletal effects (including those in the tail) are secondary to a systemic tendency to epidermal hyperplasia.

4. The hyperplastic regions of the apical ectodermal ridge and of the limb epidermis start to keratinize (parakeratosis) in the 13-day stage whereas in normal development keratinization of the skin does not start until some 3 days later.
The effects on litter size of crossing lines of mice inbred without selection
Authors: Roberts R. C.
Published: September 2009

1. The experiment was designed to provide basic information relevant to the utilization of heterosis in animal improvement. The character studied was the size of the first litter in mice.

2. Thirty inbred lines were crossed at random when the inbreeding coefficient reached 0·50 (three full-sib matings). The lines had been inbred without selection except for natural selection operating with lines.

3. The mean litter size of the crossbred mice did not exceed that of the outbred population from which the inbred lines had been derived. This indicates that the increased litter size normally associated with crossbred mice must be ascribed to some form of selection other than within-line natural selection.

4. Estimates were obtained of the variance components associated with general and special combining abilities. As anticipated, these estimates were very small, especially those relating to special combining ability. Before selection between crosses becomes possible, high levels of inbreeding must be achieved.
The genetic sensitivity to X-rays of mouse foetal gonads
Authors: Carter T. C. , Lyon Mary F. , Phillips Rita J. S.
Published: September 2009

The mutation rate at seven specific loci was measured among the offspring of male and female mice exposed as 17½-day-old foetuses to 200 r. X-rays. In the female series the mutation rate was lower, by a factor of about four, than the comparable adult rate; in the male series the mutation rate was lower but not statistically significantly lower than in adults.
Effect of inbreeding on ovulation rate and foetal mortality in mice
Authors: Falconer D. S. , Roberts R. C.
Published: September 2009

Dissections were made of 16-day-pregnant female mice with the object of discovering the developmental stage at which litter size is reduced by inbreeding. Counts were made of the numbers of corpora lutea, implantation sites, and live embryos, and comparisons were made between females with inbreeding coefficients of 50–60% and non-inbred females. Except in one group the embryos were all non-inbred, so that the comparisons showed the effect of inbreeding in the mother of the litter. No influence of inbreeding in the male parent was found.

The only difference found between inbred and non-inbred females was in the number of eggs or embryos lost before implantation. The greater pre-implantation loss in inbred females was enough to account for the smaller number of young born alive in their litters.

There was no difference between the inbred and non-inbred females in the ovulation rate, measured by the number of corpora lutea, or in the post-implantation mortality of the embryos.

There was a positive correlation between ovulation rate and weight at 6 weeks. For reasons explained in the Discussion, the inbred females did not differ in weight from the non-inbred females. If, under other conditions, the weight declined on inbreeding, the ovulation rate would be expected to decline also.
Genetical studies on the skeleton of the mouse XXVI. Pintail
Authors: Berry R. J.
Published: September 2009

1. The gene for Pintail (symbol Pt) shows no dominance. Heterozygotes are viable and fertile; many homozygotes die early in life, but the survivors appear to breed normally. Pt reinforces the effects of Sd and T on the tail; there is no evidence for interaction between Pt and + /vt.

2. The gene produces a shortening of the tail, but the most marked effect on the adult is in the great reduction of the nucleus pulposus of the intervertebral discs, which may lead to tail kinks in some animals.

3. Pintail embryos can be recognized from the eleventh day stage of development onwards by the possession of a much smaller notochord than normal. This reduced notochord is the result of a reduced rate of cell division which first manifests itself in 10-day embryos. Perhaps this reduced rate is the result of altered relations of the notochord with tail-gut and neural tube in 10-day embryos.
The cytology of Aspergillus nidulans
Authors: Elliott Charles G.
Published: September 2009

In haploid strains of Aspergillus nidulans, asci arise from croziers. The two nuclei of the young ascus (the penultimate cell of the crozier) fuse, and the zygote nucleus immediately undergoes meiosis. At diakinesis and first metaphase eight bivalents are seen: three large (one, Chromosome 2, with a satellite), two medium sized (Chromosomes 4 and 5), two small (Chromosomes 6 and 7) and one very small (Chromosome 8). The perithecia of haploid strains are packed with asci and have very few sterile hyphae.

Diploid strains (heterozygotes made by Roper's technique) are very different from haploids in that the perithecia contain many sterile hyphae with little cytoplasm and coiled hyphae with dense cytoplasm made up mainly of uninucleate cells, and there are few asci in a perithecium. Croziers are absent: some of the cells of the coiled hyphae become asci. At diakinesis and first metaphase, the same chromosome configurations are seen as in a cross between the haploid strains from which the diploid was synthesized; the chromosomes are bivalents. The young ascus thus has a single (diploid) nucleus which undergoes meiosis, and asci develop apogamously. No evidence of nuclear fusion in the young ascus and of a tetraploid meiosis was obtained. Cultures from ascopores isolated by micro-manipulation from perithecia of diploids were all haploid. Meiosis appears to proceed normally to first metaphase, but typical later stages, and asci with spores, are rarely seen. First anaphase frequently fails to occur, and the chromosomes clump together.

In the strain ad2 y, obtained from a normal strain by X-irradiation, nine bivalents are present, one a very small fragment. In crosses between ad2 y and a normal strain, and in a diploid made from them, the fragment pairs with Chromosome 6. Asci in the cross between ad2 y and a normal haploid are highly irregular, often with less than the usual eight spores.
Structural polymorphism in Drosophila subobscura Coll. from various localities in Scotland
Authors: Knight G. R.
Published: September 2009

1. Gunson's salivary chromosome preparations of Drosophila subobscura from widely separated sites in Scotland have been re-examined and inversions recorded according to the Mainx nomenclature.

2. Sixty-four diploid sets only were available. Of these, thirty-seven sets were found to be structurally homozygous on all chromosomes.

3. From Drumnadrochit in the north-central area of Scotland, the inversion found on the E-chromosome, so far as is known, has not previously been described. Its break-points have been noted, and the inversion is named E14.

4. A strain of D. subobscura from the small western island of Iona was the only one found to be completely homozygous in the five long arms of the chromosome set.

5. Samples of D. subobscura from two closely related localities in Midlothian, Scotland, also have been examined. Results are based on the analysis of 120 haploid sets in hybrids between the local race and the standard Küsnacht stock.

6. A slight difference in type and frequency of inversions has been noted between the two populations. The inversion E1+2 was recorded from Dalkeith, but was absent at Heriot, while U1, present at Heriot, was replaced by UST at Dalkeith.

7. The A-chromosome was structurally homozygous throughout.

8. Scottish samples of D. subobscura are characterized by their qualitative simplicity of polymorphism, the variety of inversion types being small. Chromosome orders analysed have been compared with those occurring in Western Europe and Israel.
Analysis of quantitative inheritance of body size in mice IV. An Attempt to isolate polygenes
Authors: Chai C. K.
Published: September 2009

The isolation of single inheritance units affecting body size in mice has been attempted. By using Large and Small mice as the parental strains, a breeding scheme has been carried out by repeated backcrossing to each strain with selection for both large and small body sizes in each backcross. The selections were started from the second backcross generations. The Small backcross was carried to the seventh generation and the Large to the fifth. Based on analysis of the means and variances for the parental strains and the backcross generations, it is tentatively concluded that a small number of, if not single, inheritance units may have been introduced from the Large to the Small mice. The ‘large’ genes appear to be dominant over the ‘small’ genes.
Heterogeneity in recombination frequencies inNeurospora crassa
Authors: Frost L. C.
Published: September 2009

The available data on heterogeneity in centromere distances for a number of loci in several linkage groups are analysed and interpreted. When the crosses are grouped according to wild-type ancestry, heterogeneity is eliminated in any one group except those which consist of backcrosses or intercrosses. Abbott 4 and 12 are shown to be the source of the heterogeneity while Lindegren and probably Chilton wild strains give consistent, homogeneous distances. In a cross between Abbott 12 and Lindegren wild-types, the centromere distances ofmtandascoshow heterogeneous values between the spore pairs in an ascus indicating that significantly different distances are genetically determined and that the factors concerned show segregation. The genetic determination differs in the various wild strains; the data suggest that at least three factors are involved. In random spore analyses heterogeneity is present in recombination frequencies between linked markers either proximal or distal to their centromere. The mechanism by which heterogeneity in the data might arise is discussed. To obtain homogeneous data it is suggested that all markers used should be repeatedly backcrossed to the Lindegren wild-type.
Sensitivity of theDrosophilatestis to tri-ethylene melamine (TEM)
Authors: Reddi O. S. , Auerbach C.
Published: September 2009

The sensitivity pattern of theDrosophilatestis to TEM was analysed by means of a dual-purpose strain that allows the scoring of induced crossovers and sex-linked lethals in the progeny of the same flies. It was found that TEM produces the highest frequency of mutations in spermatocytes or late spermatogonia, while early spermatogonia are even less sensitive than mature spermatozoa. The discrepancy between this conclusion and that obtained by Fahmy & Fahmy (1955) is attributed to a difference in the method of analysis. The sensitivity pattern of theDrosophilatestis to TEM resembles that to mustard gas and differs from that to X-rays. The sensitivity pattern of the mouse testis to TEM differs from that of theDrosophilatestis.
Asymmetrical response to selection for rate of development inDrosophila subobscura
Authors: Clarke Jean M. , Smith J. Maynard , Sondhi K. C.
Published: September 2009

Starting from a geographically hybrid foundation population ofDrosophila subobscura, selection for fast and for slow development has been practised without inbreeding on a diet with an unusually high level of protein. Realized heritabilities in the fast and slow lines were + 0·063 ± 0·029 and + 0·186 ± 0·031 respectively. A half-sib analysis of the foundation population and full-sib analyses of the first two and the last two selected generations were carried out. Hybrids between the two lines were approximately intermediate between their parents.

Two types of genetic explanation of the asymmetrical response are discussed. The first assumes directional dominance of alleles for fast development. Such an assumption can explain the asymmetrical response, but runs into difficulties in explaining the nature of the genetic variance in the selected populations and the intermediacy of the hybrids between the two lines.

A second assumption, which appears to fit the facts better, is that there exists a ‘developmental barrier’ preventing development at a rate appreciably faster than that of the foundation population. In physiological terms this implies that more rapid development requires a more profound modification of the population than could be achieved by a few generations of selection. In genetic terms, it implies epistatic interactions between genes at different loci: gene substitutions at a given locus which increase development rate on a genetic background causing slow development have little or no effect on a genetic background causing rapid development. In other words, there is a law of diminishing returns as more and more alleles for fast development are accumulated in the genotype. It is suggested that genetic situations of this kind may be common in populations which have been exposed to directional selection for a long time in reasonably large populations, either in nature or in domestication.
Linkage relations and some pleiotropic effects of the dreher mutant of the house mouse
Authors: Lyon Mary F.
Published: September 2009

Linkage studies with the mutant dreher (dr) of the mouse (Mus musculus L.) have shown that it lies in linkage group XIII and that the order of loci is dr–Dh–ln. The recombination between dr and Dh was 22·3 ± 4·1%.

Two previously undescribed pleiotropic effects of the dr gene were observed. The first was a tendency to white spotting in the belt region, and the second an interaction with brachyury (T) such that drdr T+ animals had shorter tails on the average than + dr T +.
Polygene analysis
Authors: Gilbert Neil
Published: September 2009

The usual conventions are relaxed to permit the introduction of a curved genetic model that shows some attractive features. Linear polygene analysis is examined in the light of this more flexible model. It is shown that great care is necessary in the choice of scale, since variances are more sensitive than means to small deviations from additivity. Inclusion of the F3 is necessary for successful prediction by extrapolation. The genetical validity of any type of polygene analysis is discussed. The new model is quite promising for the analysis of means; but I think that the (more ambitious) analysis of variances is likely to remain intractable, for both genetical and statistical reasons.
Effects of dominance and size of population on response to mass selection
Authors: Kojima Ken-Ichi
Published: September 2009

A theory of mass selection in a small population was developed, and the mean change in gene frequencies, the variance of gene frequency changes and the expected gain in the mean phenotypic value of an offspring population were formulated in terms of a generalized selection differential and the additive and dominance effects of genes.

The magnitude of the variance of changes in gene frequency was compared with the magnitude of the variance expected from the genetic random drift in a population with the same gene frequency and of the same size in absence of selection. The former was found to be usually smaller than the latter when the gene frequency ranged from intermediate to high and when selection was directed for a high performance.

The usual prediction equation for gain from selection in an infinite population was compared with the expected gain formula derived for a small population. The size of the population did not cause a serious difference between the two expected gains when there was no dominance effect of genes. Dominance alone could cause the usual prediction to be slightly more biased. The joint effects of the finite size of population and dominance gene action could amount to a considerable bias in the usual prediction equation. Such a bias can be, in the main, accounted for by the inbreeding depression.
The ecological genetics of growth inDrosophila4. The influence of larval nutrition on the manifestation of dominance
Authors: Robertson Forbes W.
Published: September 2009

(1) Two lines have been selected for small wing cell size from the cage Pacific population. Body size was reduced by about 10% and 15% in the two lines which did not regress when selection was relaxed.

(2) The effects of crossing each line to the unselected population has been determined in a number of repeated tests on the live yeast medium and also on various sub-optimal synthetic media.

(3) The size of the F1, relative to the size of the parents, is greatly influenced by the composition of the larval diet. The F1may coincide with the mid-parent value but generally significantly exceeds it and is often the same size as the unselected parent population.

(4) In crosses to an unselected population on alternative media the F1was either the same size as the unselected population or exceeded it.

(5) Crosses between the selected lines produced an F1which exceeded the larger parent but remained well below the level of the unselected population.

(6) To test for interaction between genes at different loci, chromosomes from the unselected population were substituted in the genetic background of each of the selected lines to provide an array of genotypes in which one, two or three pairs of major chromosomes had homologues derived from different strains. Leastsquares analysis indicated differences between the lines in the distribution of effects among the chromosomes together with the presence of interaction between chromosomes and this was greater for the substitutions in the line which showed the greater consistency of recessive behaviour in crosses to the unselected population.

(7) At the end of the selection experiment two lines were selected for large body size from the F2of the cross between the two selected lines. Both responded to selection for three to four generations and then fluctuated at a level slightly below that of the unselected population.

(8) The physiological changes which involve correlated changes in body and cell size differ from those which result from selection for smaller body size, at least in the early stages of such selection, and are associated with differences in genetic behaviour. The apparently recessive property, which involves extensive non-allelic interaction, is progressively established during the course of selection. Apparently selection for smaller cell size is particularly effective in disturbing the normal homeostasis of growth and is accompanied by relatively greater loss of heterozygosis than is likely with equivalent reduction in size due to selection for smaller body as opposed to cell size.