bluuebunny/crossref_metadata_2025 huggingface dataset:
The relationship between positive development and psychopathology during the transition to adulthood: A person‐centred approach
Authors: O’Connor Meredith , Sanson Ann , Hawkins Mary T. , Olsson Craig , Frydenberg Erica , Toumbourou John W. , Letcher Primrose
Published: November 2011

The transition to adulthood is characterised by potential for both positive development and problem outcomes such as psychopathology, yet little is known about relationships between the two. Given the diversity of pathways observed during this transition period, there is likely to be significant heterogeneity in young people’s experiences of these outcomes. Drawing on data from 1158 19–20 year olds in the Australian Temperament Project and using latent profile analysis, we identified six subgroups. For most, higher positive development was associated with lower psychopathology and vice versa. One group (33.6%) was high across all positive development measures and low on psychopathology, and another (47.7%) average in both areas. The remaining four groups were low on positive development but differentiated by average psychopathology (4.7%), high internalising (5.5%), and moderate (7.2%) and severe (1.3%) externalising problems. Tailored intervention strategies that address both the promotion of competence and prevention of problem outcomes are needed.
Documenting different domains of promotion of autonomy in families
Authors: Manzi Claudia , Regalia Camillo , Pelucchi Sara , Fincham Frank D.
Published: November 2011

Parental promotion of autonomy for offspring well‐being has been widely recognized in developmental psychology. Recent studies, however, show that this association varies across cultures. Such variation may reflect inappropriate measurement of this dimension of parenting. Therefore, three existing measures of promotion of autonomy were used to derive different dimensions related to the promotion of autonomy in three different domains – promotion of autonomous thought, promotion of autonomous decision‐making, and promotion of physical separation. The cross‐cultural significance of this three‐component model was tested in samples of late adolescents (n = 1361) from four nations‐ the US, Belgium, Italy and China. Data from all four countries best fit a three dimensional model but the covariance between the three dimensions was moderated by culture. Culture also moderated the impact of promotion of autonomy on offspring well‐being.
Cervical Dermoid Sinus in a Cat: Case Presentation and Review of the Literature
Authors: Fleming Jamie M , Platt Simon R , Kent Marc , Freeman Anne C , Schatzberg Scott J
Published: November 2011

A 6-month-old female spayed domestic shorthair cat was presented for evaluation of a focal subcutaneous swelling on the dorsal neck at the level of atlas. The magnetic resonance imaging and surgical treatment of a dermoid sinus associated with the cervical vertebrae is described. To the authors' knowledge, a dermoid sinus in this location has not been described previously in the cat. The prognosis following surgical resection appears favorable.
Phenotypic and genetic analyses of 111 clinical and environmental O1, O139, and non-O1/O139Vibrio choleraestrains from different geographical areas
Authors: SELLEK R. E. , NIEMCEWICZ M. , OLSEN J. S. , BASSY O. , LORENZO P. , MARTÍ L. , ROSZKOWIAK A. , KOCIK J. , CABRIA J. C.
Published: November 2011

A total of 111 clinical and environmental O1, O139 and non-O1/O139Vibrio choleraestrains isolated between 1978 and 2008 from different geographical areas were typed using a combination of methods: antibiotic susceptibility, biochemical test, serogroup, serotype, biotype, sequences containing variable numbers of tandem repeats (VNTRs) and virulence genesctxAandtcpAamplification. As a result of the performed typing work, the strains were organized into four clusters: cluster A1 included clinical O1 Ogawa and O139 serogroup strains (ctxA+andtcpA+); cluster A2 included clinical non-O1/O139 strains (ctxA−andtcpA−), as well as environmental O1 Inaba and non-O1/O139 strains (ctxA−andtcpA−/tcpA+); cluster B1 contained two clinical O1 strains and environmental non-O1/O139 strains (ctxA−andtcpA+/tcpA−); cluster B2 contained clinical O1 Inaba and Ogawa strains (ctxA+andtcpA+). The results of this work illustrate the advantage of combining several typing methods to discriminate between clinical and environmentalV. choleraestrains.
Relationship between the level of antibodies in bulk tank milk and the within-herd seroprevalence of Coxiella burnetii in cows
Authors: TAUREL A.-F. , GUATTEO R. , JOLY A. , BEAUDEAU F.
Published: November 2011

The relationship between the level of antibodies in bulk tank milk (BTM) and the within-herd seroprevalence of Coxiella burnetii in cows was assessed. Blood from milking cows and BTM were sampled in 55 infected herds and tested using commercial enzyme-linked immunosorbent assay (ELISA) kits. The relationship between antibody levels and WHP, which was quantified using a general linear model, was only moderate (R2=0·15). Nevertheless, the lowest antibody level in BTM was associated with the lowest mean within-herd prevalence. The present finding indicates that ELISA applied to BTM could identify infected herds with quite low within-herd seroprevalence. For such herds, the vaccination of dairy cows as well as nulliparous heifers using a phase I vaccine could effectively prevent C. burnetii shedding.
Receptive vocabulary differences in monolingual and bilingual adults
Authors: BIALYSTOK ELLEN , LUK GIGI
Published: November 2011

English receptive vocabulary scores from 797 monolingual and 808 bilingual participants between the ages of 17 and 89 years old were aggregated from 20 studies to compare standard scores across language groups. The distribution of scores was unimodal for both groups but the mean score was significantly different, with monolinguals obtaining higher standard scores than bilinguals. Consistent with previous research, older adults had higher vocabulary scores than younger adults. The results are discussed in terms of the implications for theoretical conceptions of linguistic processing and clinical diagnosis in bilingual populations.
Ambiguous symbolisms: recognising customary marriage and same-sex marriage in South Africa
Authors: Barker Nicola
Published: November 2011

In this article I draw on the South African legal context to critique the argument that same-sex marriage would provide ‘equal recognition’ for same-sex relationships. I highlight the ways in which, despite strong equality provisions in the South African Constitution and an apparent commitment to substantive rather than merely formal equality, both customary marriage and same-sex marriage continue to be subordinate to heterosexual civil marriage. I then broaden my analysis to consider the extent to which this would also be the case in other jurisdictions, particularly the UK. Drawing on the Butler/Fraser debate on recognition and redistribution, I argue that there is a connection between misrecognition and material disadvantage that goes unacknowledged in ‘symbolic recognition’ claims for same-sex marriage. The critiques of ‘marriage equality’ should sound a warning not only to same-sex marriage advocates but also more generally to those who would seek ‘equal recognition’ through law reform.
Movement patterns by Egernia napoleonis following reintroduction into restored jarrah forest
Authors: Christie Kimberley , Craig Michael D. , Stokes Vicki L. , Hobbs Richard J.
Published: November 2011

Context
The value of animal reintroduction as a conservation tool is debated. This is largely because the limited quantity of research that has been conducted on animal reintroductions has shown varying degrees of success in establishing new populations. The reasons why some reintroductions are successful, whereas others are not, are often not clear.

Aims
The present research aims to determine whether reptile reintroduction into restored mine pits is a potential management technique for managing and conserving reptile populations within a mined landscape.

Methods
Twelve Napoleon’s skinks were trapped then fitted with 0.9-g transmitters. Half were reintroduced into 5-year-old restored mine pits and the other half into unmined forest. Bodyweights, movement patterns and macro-habitat selection were recorded weekly during November and then monthly until March.

Key results
Skinks reintroduced into restored sites quickly moved into unmined forest. Both groups of skinks moved large distances, but those reintroduced into restored sites travelled further than did control skinks and took longer to reduce their distances travelled, showing possible stress as a result of release into unsuitable habitat. Eventually, almost all skinks found suitable habitat in unmined forest and settled into these areas while continuing to gain weight.

Conclusions
Reintroduction was an ineffective technique for facilitating colonisation of restored minesites by Napoleon’s skink. Lack of suitable micro-habitats within restoration areas, such as ground logs and coarse, woody debris piles, is likely limiting the use of these areas by Napoleon’s skinks and is likely to be the cause of their failure to remain or settle in restored sites after reintroduction.

Implications
Determining the habitat requirements of skinks and replicating this in restoration sites would seem the more appropriate management option than is reintroduction, and this may be the case for other reptiles and habitat specialists.
Resultant muscle torque and electromyographic activity during high intensity elastic resistance and free weight exercises
Authors: Aboodarda Saied Jalal , Hamid Mohamad Shariff A. , Che Muhamed Ahmad Munir , Ibrahim Fatimah , Thompson Martin
Published: November 2011

The purpose of this study was to quantify and compare Resultant Muscle Torque (RMT) and muscle activation (EMG) pattern, during resistance exercise comprising eight repetitions maximum (8 RM) biceps curl with elastic resistance and free weight exercise. Sixteen male and female recreationally active subjects completed 8 RM biceps curl by each of three modalities of resistance exercise: (i) dumbbell (DB), (ii) elastic tubing with original un‐stretched length at the commencement of contraction (E0), and (iii) elastic tubing with 30% decrement of original length (E30) at the commencement of contraction. The magnitude of muscle activation, external force, acceleration as well as range of motion (ROM) were quantified and synchronised by specific software. The data were collected from all eight repetitions but the first (initial), the fifth (middle) and the eighth (last) repetitions were selected for further data analysis. Each selected repetition was partitioned into a concentric and eccentric phase and then each phase was further divided into three equal segments (3 concentric and 3 eccentric = 6 segments per repetition). The EMG and RMT data demonstrated a bell‐shaped muscle activation and muscle torque production pattern for the three modes of exercise. The E30 resulted in 15.40% and 14.89% higher total EMG (µV) as well as 36.85% and 17.71% higher RMT (N · m) than E0 and DB, respectively (all P <0.05). These findings support the contention that an elastic resistance device (E30) has the capacity to provide an appropriate high resistance stimulus to meet the training requirement of elite athletes.
Transmission of 2009 Pandemic Influenza A (H1N1) Virus among Healthcare Personnel—Southern California, 2009
Authors: Jaeger Jenifer L. , Patel Minal , Dharan Nila , Hancock Kathy , Meites Elissa , Mattson Christine , Gladden Matt , Sugerman David , Doshi Saumil , Blau Dianna , Harriman Kathleen , Whaley Melissa , Sun Hong , Ginsberg Michele , Kao Annie S. , Kriner Paula , Lindstrom Stephen , Jain Seema , Katz Jacqueline , Finelli Lyn , Olsen Sonja J. , Kallen Alexander J.
Published: November 2011

Objective.

In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak.

Design.

Cohort study.

Setting.

Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009.

Participants.

Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States.

Methods.

Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use.

Results.

Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings.

Conclusions.

pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.
Effect of pulse width on the production of radicals and excited species in a pulsed positive corona discharge
Authors: Ono Ryo , Nakagawa Yusuke , Oda Tetsuji
Published: November 2011

The effect of pulse width on the production of various radicals and excited species (OH, O, O3,

,

, OH(A 2Σ), O2(v)) in a pulsed positive corona discharge is measured. The densities of these species are measured using laser-induced fluorescence, light absorption and optical emission spectroscopy. It is shown that the pulsed corona discharge can be divided into three phases related to the production of radicals and excited species: (i) primary streamer, (ii) earlier part of secondary streamer and (iii) later part of secondary streamer. It is shown that phase (iii) is inefficient for the production of most of the radicals and excited species. Therefore, a short pulse is desirable for efficient production of radicals and excited species to cut off the inefficient later part of the secondary streamer.
Temporal motifs in time-dependent networks
Authors: Kovanen Lauri , Karsai Márton , Kaski Kimmo , Kertész János , Saramäki Jari
Published: November 2011

Temporal networks are commonly used to represent systems where connections between
elements are active only for restricted periods of time, such as telecommunication, neural
signal processing, biochemical reaction and human social interaction networks. We
introduce the framework of temporal motifs to study the mesoscale topological–temporal
structure of temporal networks in which the events of nodes do not overlap in time.
Temporal motifs are classes of similar event sequences, where the similarity refers not only
to topology but also to the temporal order of the events. We provide a mapping from event
sequences to coloured directed graphs that enables an efficient algorithm for identifying
temporal motifs. We discuss some aspects of temporal motifs, including causality and
null models, and present basic statistics of temporal motifs in a large mobile call
network.
Expression of chemosensory proteins in the tsetse fly Glossina morsitans morsitans is related to female host‐seeking behaviour
Authors: Liu R. , He X. , Lehane S. , Lehane M. , Hertz‐Fowler C. , Berriman M. , Field L. M. , Zhou J.‐J.
Published: November 2011

Chemosensory proteins (CSPs) are a class of soluble proteins present in high concentrations in the sensilla of insect antennae. It has been proposed that they play an important role in insect olfaction by mediating interactions between odorants and odorant receptors. Here we report, for the first time, the presence of five CSP genes in the tsetse fly Glossina morsitans morsitans, a major vector transmitting nagana in livestock. Real‐time quantitative reverse transcription PCR showed that three of the CSPs are expressed in antennae. One of them, GmmCSP2, is transcribed at a very high level and could be involved in olfaction. We also determined expression in the antennae of both males and females at different life stages and with different blood feeding regimes. The transcription of GmmCSP2 was lower in male antennae than in females, with a sharp increase in 10‐week‐old flies, 48 h after a bloodmeal. Thus there is a clear relationship between CSP gene transcription and host searching behaviour. Genome annotation and phylogenetic analyses comparing G. morsitans morsitans CSPs with those of other Diptera showed rapid evolution after speciation of mosquitoes.
The heat transfer between a heated tip and a substrate: Fast thermal microscopy
Authors: Dransfeld K. , Xu J.
Published: November 2011

Here we describe a new mechanism of heat transfer between two solids separated by a distance. This mechanism does not involve the ambient air or adsorbed vapour films, and is therefore expected to remain active under perfect vacuum conditions. As will be described in detail, thermal charge fluctuations of one solid substrate kept at finite temperatures create an electromagnetic field—at infrared frequencies and of a short coherence length—which extends across the gap and effectively transports heat to the other solid. In our view this mechanism is responsible for the effective heat transfer observed recently by C. C. Williams and H. K. Wickramasinghe between a heated tip and a substrate.
Lateral resolution of the scanning tunnelling microscope
Authors: Laloyaux Th. , Lucas A. A. , Vigneron J.‐P. , Lambin Ph. , Morawitz H.
Published: November 2011

A theoretical study of the current distribution in a model which extracts the prominent characteristics of a tip‐surface geometry in a scanning tunnelling microscope is presented. The sample is a Sommerfeld metal with a planar surface while the tip, also made of a Sommerfeld metal with a planar surface, presents a hemispherical protrusion. Schrödinger's equation is solved by using a form of the finite element method suitable to treat the three‐dimensional tunnelling problem.

We have derived the current distribution for several values of the protrusion radius and for various gaps between the electrodes. From these results, we investigate the ideal resolution of the scanning tunnelling microscope for realistic values of these geometrical parameters.

Though applied to a rather simple model, at this stage, our method appears to be a suitable scheme for further, more refined computations, accounting for the detailed atomic structure of the electrodes.
Tunnelling accelerometer
Authors: Baski A. A. , Albrecht T. R. , Quate C. F.
Published: November 2011

Due to the strong distance dependence of tunnelling current on electrode spacing, tunnelling can be used to measure sub‐ångström‐scale displacements. The sensitivity and relative simplicity of this technique make it well suited for applications in highly sensitive accelerometers. We have constructed a cantilever‐type accelerometer in which a mass‐loaded lever deflects freely in response to accelerations. Deflection is measured by tunnelling in the constant current mode between an electrode on the lever and a tunnelling tip positioned by a piezoelectric transducer. Using a lever/mass system with a force constant of 2·3 × 104N/m and an effective mass of 2·4g, we obtained a sensitivity of 79 V/g with a bandwidth greater than 200 Hz. Accelerations smaller than 10−4g could be detected using this device.
On some New Parasites
Authors: Richter H. C. , Blankley Frederick
Published: November 2011

On some New Parasites

The New Metallic Covered Glass Chimney.

How to Select Spectacles for Near‐sight and Far‐sight.
VI.—EXTRA‐FRUSTULAR DIATOMS
Authors: Hendey N. Ingram
Published: November 2011

Synopsis.

FRESHLY gathered marine diatoms when placed upon an agar medium ejected their protoplasmic masses from the siliceous frustules. The naked cells, enclosed within an intact perizonium, continued to live upon a solid medium for more than nine months, during which they lost their normal shape and power of locomotion. When the cells were returned to an aqueous medium, either static or flowing, they became rehabilitated, re‐establishing their naviculoid form and regaining their power of movement.

This work was undertaken at the Admiralty Central Metallurgical Laboratory, Emsworth, and forms part of a general investigation into the r81e of “first colonist” organisms on surfaces immersed in seawater, in connection with the antifouling problem of ships' hulls.
OBSEEVATIONS ON PRIMARY LIVER CARCINOMA IN WEST AFRICAN SOLDIERS
Authors: Findlay G. M.
Published: November 2011

SYNOPSIS.

Of 60 malignant tumours occurring among 227,000 West African soldiers, from 1940 to 1945, 37 were primary liver carcinomata. *The cause of this high incidence of liver cancer is considered to be a diet deficient in sulphur‐containing amino acids, associated with infective hepatitis, malaria, alcohol, and other toxins.
THE STRUCTURE AND PROGRESSION OP VESICAL TUMOURS INDUCED IN MICE BY 2‐ACETYLAMINOPLUORENE
Authors: Foulds L.
Published: November 2011

SYNOPSIS.

Nine vesical tumours induced in mice by 2‐acetylaminofluorene were studied histologically and three were transplanted in series. Four tumours were invasive and two of them had disseminated in the peritoneal cavity. Histologically the tumours ranged from squamous‐ or transitional‐celled papillomata to spindle‐ or pleomorphic‐celled tumours without distinctively epithelial characters.

For reasons which are discussed, the origin of all the varied tumour cells is traced to the transitional epithelium of the bladder. Different tumours represent different stages in one neoplastic process leading, as a result of irreversible qualitative changes or “progression” in the tumour cells, from localized papilloma to disseminating undifferentiated carcinoma, a sequence observed during serial transplantation of one tumour. Progression does not always reach its end‐point in a primary tumour. It continues in transplanted tumours in normal mice and independently of the inciting carcinogen. Progression is focal in occurrence. Alternative paths of progression lead to different end‐points.
CYTOLOGICAL CHARACTERISTICS OF FIBROBLASTS AND SARCOMA CELLS DEMONSTRABLE BY PHASE‐CONTRAST MICROSCOPY
Authors: Ludford R. J. , Smiles J.
Published: November 2011

SYNOPSIS.

Fibroblasts from subcutaneous connective‐tissue and from the stroma of tumours, and also sarcoma cells of a rapidly growing transplantable tumour have been studied by phase‐contrast microscopy. This technique demonstrates very clearly the increased mitochondrial content of the cytoplasm of the malignant cells and the more hyperchromatinic character of their nuclei. The cells comprising a small fragment taken from the periphery of a rapidly growing tumour exhibit a wide range of structure which deviates considerably from the cellular organization which is regarded as the morphological expression of most active malignant growth. Both the large nucleolar content of the nuclei (oxyribose nucleotides) as well as the considerable amount of chromatin (desoxyribose nucleotides) appear to be used up in the formation of the chromosomes at the prophase. Either the oxyribose nucleotides must be converted to the desoxyribose type during chromosome formation, or else the chromosomes must contain a considerable proportion of oxyribose nucleotides. During the reconstruction phase of mitosis the cytoplasm grows and the mitochondria increase in numbers before the nuclei have returned to the “resting” condition and reconstituted their nucleoli. The sarcoma cells readily undergo cytoplasmic budding (potocytosis). The intensity of this process seems to be correlated with the fluidity of the cytoplasm.
RECENT PENEROPLIDÆ. PART I
Authors: Hofker J.
Published: November 2011

SYNOPSIS.

Here, and in future parts of this paper, an attempt has been made to re‐group genera and species of recent Peneroplidœ and associated forms by a careful study of external ornamentation, form of the aperture, mode of coiling, and other characters, after a large number of specimens had been examined. The origin, phylogeny, and geological history of the group are also outlined. Two new genera and six new species are described. Observations are made on the reproduction and geographical distribution of species in the last part with an outline of the systematics.
VII.—SLIDES AND COVER‐GLASSES FOR DARK‐GROUND MICROSCOPY
Authors: Pijper A. , Kistner A.
Published: November 2011

SYNOPSIS

The suitability of slides and cover‐glasses for dark‐ground microscopy is discussed.

Slides and cover‐glasses to be used for dark‐ground microscopy have to be particularly clean and free from scratches. Dirt and scratches interfere with the dark‐ground effect. The stronger the source of light that is used, the more numerous and the more troublesome such blemishes become.
IX—MICROSCOPIC OBSERVATION OF LIVING CELLS DURING FREEZING AND THAWING
Authors: Smith A. U. , Polge C. , Smiles J.
Published: November 2011

SYNOPSIS

A freezing slide has been constructed for obtaining very low temperatures on the microscope stage, and an optical system evolved for studying the process of freezing and thawing by direct visual observation, micro‐projection, or photomicrography.

The behaviour of suspensions of fowl spermatozoa, rabbit red blood corpuscles, and amœbae, when frozen and thawed, has been studied. In presence of glycerol the processes of crystallization and dissolution are modified, spermatozoa resume full motility, and blood corpuscles are preserved from haemolysis. Intracellular crystallization has so far been observed only in amoebae, which fail to revive on thawing.

The mode of action of glycerol in preserving some cells from death at low temperatures is discussed.
X.—CORRELATION BETWEEN ELECTRON AND OPTICAL MICROSCOPICAL EXAMINATION OF METAL SURFACES
Authors: Perryman E. C. W. , Vernon‐Smith Sheila
Published: November 2011

Synopsis

Examples are given of the correlation between the images of metallurgical preparations as observed in the light microscope, with and without phase contrast, and (via the intermediary of a plastic replica) in the electron microscope. These illustrate the difficulties of unambiguous interpretation and show the need for a more critical, preferably comparative, approach in metallurgical microscopy.
XVIII.—POLYETHYLENE GLYCOLS AS HISTOLOGICAL EMBEDDING MEDIA: WITH A NOTE ON THE DIMENSIONAL CHANGE OF TISSUE DURING EMBEDDING IN VARIOUS MEDIA
Authors: Miles A. E. W. , Linder J. E.
Published: November 2011

Synopsis

The literature is reviewed. A technique for embedding tissues in polyethylene glycol 1,000 mono‐stearate (Nonex 63B) after preliminary infiltration with polyethylene glycol 900 is described. Preliminary dehydration in alcohol is not required and at no stage is the temperature of the tissue raised above 40° C. Measurement of tissue before and after embedding in Nonex, paraffin and celloidin shows that there is significantly less shrinkage in Nonex. It is shown that the celloidin in celloidin‐Nonex mixtures used experimentally for embedding penetrates tissue. The difficulty of mounting Nonex sections is discussed. Nonex sections stain well, phosphatase activity is well preserved and at least part of the lipid is preserved. It is concluded that the use of Nonex is specially indicated for tissues liable to shrinkage artefacts and may have some advantage for histo‐chemistry.
III.—A VECTOR THEORY OF PHASE CONTRAST AND INTERFERENCE CONTRAST. III. NEGATIVE PHASE CONTRAST
Authors: Barer R.
Published: November 2011

Synopsis

The vector method developed in previous papers of this series has been applied to certain problems in negative phase contrast. Unlike positive phase contrast, increasing the absorption of the phase plate increases the range of phase change in the object over which contrast remains unreversed (i.e. bright). As absorption approaches 100 p.c., conditions change over smoothly to central dark‐ground illumination, in which all object details appear brighter than the background. In negative phase contrast it is preferable to have the retardation ψ produced by a phase plate greater than 90°, whereas in positive phase contrast ψ should be less than 90°. Maximum sensitivity occurs when ψ = 90°, in each case. The characteristic of the phase plate needed to give maximum contrast for a given phase detail are discussed.
A NEW MICROSCOPE‐LAMP
Authors: Baker John R.
Published: November 2011

SYNOPSIS

In this new lamp, the source of light is an ordinary domestic pearl bulb. In front of this is placed a bull's‐eye, which prevents the formation of an image of the pearl surface in the plane of the object and produces even illumination over the whole field of view. Since the illuminated surface of pearl glass is large, the whole of the aperture of any condenser is filled with light. The illumination is suitable for all objectives from 16 mm. (and more, if a low‐power substage condenser is used) to 2 mm., without change of bull's‐eye. Very exact setting of the direction of the beam of light is not necessary. It is claimed that this simple lamp gives the best possible illumination in all cases in which intensity of light is not the main consideration.
AN IMPROVED SINGLE‐AXIS ROTATION APPARATUS FOR THE STUDY OF CRYSTALS UNDER THE POLARIZING MICROSCOPE
Authors: Hartshorne N. H. , Swift P. McL.
Published: November 2011

SYNOPSIS

The paper describes an apparatus for rotating a small crystal about a single axis while it is immersed in a liquid of known refractive index, for use with the polarizing microscope. An auxiliary apparatus for mounting the crystal in a desired orientation with reference to the axis of rotation is also described.
ON A POSSIBLE EXPLANATION OF THE SUDDEN DOUSING OF THE LIGHT BY THE NEW ZEALAND GLOW‐WORM (ARACHNOCAMPA LUMINOSA)
Authors: Gatenby J. Brontë , Ganguly Gouri
Published: November 2011

SYNOPSIS

The New Zealand Glow‐worm (Arachnocampa luminosa) is able suddenly to douse its light when alarmed. A suggestion is made as to how this could take place.
IV.—ELECTRON MICROSCOPE STUDIES ON HUMAN DENTAL ENAMEL
Authors: Little K.
Published: November 2011

SYNOPSIS

Developing and mature dental enamel, together with early carious lesions, have been examined, using both the electron microscope and X‐ray diffraction. The most abundant component in enamel is calcium phosphate, the crystallites of which are embedded in an organic matrix. This matrix has two main components, one of which, β‐keratin, has a greater density than the second, a protein. It is this less dense protein which is first attacked and removed during the onset of dental caries—without this initial solution the remainder of the carious process would not take place.

It is suggested that the results of this investigation, together with reported facts, are consistent with there being a vitamin required for the correct formation of the protein matrix, analogous to the need of vitamin A for the formation of bone matrix. If this is so, then caries could be regarded as a vitamindeficiency disease, complicated by a secondary bacterial invasion.
HETEROTOPIC GRAFTING OF THE SPINAL CORD IN XENOPUS LÆVIS (DAUDIN)
Authors: Hughes A. , Tschumi P. A.
Published: November 2011

SYNOPSIS

Lengths of the spinal cord of young larvæ of Xenopus were grafted into the ventral body wall of host tadpoles of the same age, together with the adjacent somites and notochord. The experimental animals were fixed at various times after the operation, and the grafts were studied in serial sections.

The dorsal root ganglia of the grafts underwent little development. Some were suppressed, and there were instances of the fusion of neighbouring ganglia. The greater part of each ganglion was occupied by a mass of undifferentiated neuroblasts, sometimes present in greater numbers than the total of cells in a normal ganglion. In most specimens it was possible to identify the individual ganglia and hence to determine the levels to which the grafted cord belonged.

Within the cord the only differentiated neurones were the primary motor cells from which arose ventral roots, dendritic processes, and ventral commissural fibres as in a normal early larva. Dorsal roots enter the cord in a normal fashion, and give off ascending and descending branches. At the caudal pole of the graft the cord regenerated, and some new irregular myotomes were formed.

The mantle layer of the cord expanded laterally and underwent a hyperplasia of about twofold in terms of number of cells per spinal segment. The large neuroblastic dorsal horn is prominent, even in instances where there are no dorsal root ganglia. As in previous experiments where the cord is deprived of any influence of the limb buds, there are no differentiated ventral horn cells. The absence of all mature neurones within the mantle layer is a further feature which suggests that the stimuli for their differentiation in normal development proceed not only from the limb but also from the spinal axis.

In contrast to the normal cord of late larval stages, no pycnotic nuclei can be seen within the mantle layer of the grafts. It is possible that its cellular hyperplasia is in part due to the absence of histogenetic degeneration.
THE EXAMINATION OF SURFACES
Authors: Page D. H.
Published: November 2011

SYNOPSIS

Attention is drawn to the inadequacy of the standard methods of qualitative assessment of surfaces, particularly for translucent specimens in the magnification range intermediate between the light and electron microscopes. The advantages of certain unconventional methods, namely metal shadowing for light microscopy, reflection electron microscopy, and scanning electron microscopy are discussed.
BIOLOGICAL EFFECTS OF U.V. IRRADIATION IN CHAOS CHAOS*
Authors: Montgomery P. O'B. , Bonner W. A. , Hundley L. L. , Ashworth C. T.
Published: November 2011

SYNOPSIS

Continuous ultraviolet irradiation of the amœgba, Chaos chaos, was accomplished by ultraviolet flying‐spot television microscopy, and the results were recorded by time‐lapse motion‐picture photography.

A study of such motion‐picture films reveals that Chaos chaos progressively reacts to ultraviolet irradiation administered in this way by:

(a) increased serration of the plasmalemma

(b) increased gelation of the cytoplasm

(c) decreased and spasmodic motion of the entire amœba

(d) formation of plasmalemma blebs

(e) portions of plasmalemma and endoplasm being pinched off into the surrounding medium, (f) sudden spasmodic contractile dissolution of the amœba into the medium.

Electron micrographs of intact irradiated amœba show the major change to be one of increased accumulation of water in the cytoplasm, without apparent alteration of plasmalemma, mitochondria, or nuclear membrane.
EXAMINATION OF ROLLER‐TUBE CULTURES WITH PHASE‐CONTRAST
Authors: Trevan D. J.
Published: November 2011

SYNOPSIS

A method of examining roller‐tube cultures, using cruciform phase‐contrast microscopy, is described.
A METHOD FOR THE ROUTINE EVALUATION OF DRY MASS FROM ELECTRON MICROGRAPHS
Authors: Silvester N. R. , Burge R. E.
Published: November 2011

SYNOPSIS

Under certain conditions the optical transmission of the negative of an electron micrograph is linearly related to the mass per unit area of the corresponding specimen. A polarizing microscope was modified so that the rotation of a polaroid in the system, which restored a photo‐multiplier current to a fixed value, was a measure of the transmission of a selected area of a micrograph placed on the stage. This null‐point method can be used in the routine evaluation of the dry mass of isolated specimens from their electron micrographs. The theory of the method is given and measurements on standard objects are described that demonstrate its validity of application. Optimum conditions for measurement are considered and experimental errors are discussed. The errors in the present measurements were estimated to be less than 6 p.c. The null‐point method was rapid and simple in operation and should be useful in statistical determinations of the mass of non‐homogeneous specimens.
A NEW HELIOSTAT FOR DARK‐GROUND MICROSCOPY
Authors: Pijper Adrianus
Published: November 2011

SYNOPSIS

Sunlight dark ground microscopy with a simple heliostat has revealed a straight tail as the origin of the flagella of most motile bacteria. This tail changes into helices (“flagella”). These show specific wavelengths, with “biplicity” and take part in agglutination. All this has also been recorded cinemicrographically on 16 mm film. Among other subjects studied and filmed with this sunlight technique were bacterial motility, other types of bacterial flagella, including those of Spirilla and Vibrios, and the effect of bacteriophage and penicillin on certain bacteria.

A description is here given of a new more elaborate heliostat which will throw a brighter and steadier beam of sunlight into the microscope, thus improving and facilitating further observations of which preliminary results are given here.
APPARATUS FOR THE STUDY OF LIVING HUMAN CELLS
Authors: Dawson Mary
Published: November 2011

SYNOPSIS

An assembly of equipment for the study of living human cells is described. It is designed to keep the cells under study living, sterile, adequately nourished, at their optimum temperature and observable throughout an experiment, and to subject them to as little light as possible. The apparatus consists of a phase‐contrast microscope, a cine camera, a micro‐flash unit, a time‐lapse unit, and a warmed perfusion chamber. The microscope, camera, and flash unit are standard, commercially available items. The time‐lapse unit, its ancillary equipment, and the perfusion chamber are of the author's design.
THEORY OF ELECTRON AUTORADIOGRAPHY
Authors: Pelc S. R.
Published: November 2011

So far autoradiography has mainly been used at the level of light microscopy and the theory of autoradiography was developed for this type of work. Whatever the intended application, the problems involved can be grouped under (a) resolving power, (b) sensitivity, and (c) technique.

An autoradiograph is prepared by bringing a specimen containing some radioactive material in contact with a photographic emulsion and storing the preparation in the dark for exposure. During the time of exposure some of the radioactive material will decay and the ionizing radiations emitted will produce latent images in the emulsion. After photographic processing the developed image will appear as an accumulation of silver grains which are seen as round black spots under the light microscope and as filamentous structures in the electron microscope.
SOME EXPERIMENTS CONCERNING THE LIMITATIONS AND ERRORS IN SIZE MEASUREMENT OF SMALL OBJECTS BY VISUAL MICROSCOPY
Authors: Charman W. N.
Published: November 2011

SYNOPSIS

The systematic errors which arise in the measurement of small, non‐periodic objects by visual microscopy are discussed, together with a method for reducing these errors by calibration with objects of known size. Such a calibration is described for the case where the diameters of circular holes and opaque disks are measured using a filar micrometer eyepiece, an oil‐immersion objective, and full‐cone illumination. Examples are given showing the influence of the numerical apertures of the condenser and objective upon the sizing errors. The results are used to derive size correction factors applicable to the measurement of any thin, high contrast object when the same sizing technique is used. Values are also given for the useful lower limits of measurement. Further experimental evidence emphasizes the difficulty of accurate measurement where the objects are of finite thickness.
LYMPH NODE STRUCTURE IN DICEROS BICORNIS
Authors: Cave A. J. E. , Aumonier F. J.
Published: November 2011

SYNOPSIS

The lymph nodes of a second young specimen of the African Black Rhinoceros (Diceros bicornis) prove to be, like those of an earlier specimen, hæmolymph nodes. An unusual (and doubtless pathological) feature thereof is a metamorphosis of the endothelial lining of the precapillary arteries within all nodes examined. Histological evidence suggests that the ordinary lymph node may assume hæmolymph characters under appropriate physiological stimulus.
ON THE STRUCTURE OF THE RETINA OF MAN AND MONKEY
Authors: Leach E. H.
Published: November 2011

SYNOPSIS

After formaldehyde fixation, three types of cone can be described in the retina of man and monkey. The differences are due to a fixation artifact but represent an inherent non‐identity, which is imperceptible after better fixation. There is no evidence to suggest that those three types perform different functions in colour vision and it is more likely that they represent different stages of activity or degeneration.

The outer segment of the cones is composed of a uniform core surrounded by a cell membrane, which is discontinuously thickened to form a thread disposed as a series of rings or a spiral, which is myelin in nature and has a high refractive index. Some of the rods show a similar structure of the outer segment, particularly in man and the baboon. Although unpigmented, the thread appears opaque when sections are examined in a mountant of low refractive index.
EXPERIMENTAL MEASUREMENTS OF DIFFRACTION IMAGES IN AXIAL INCIDENT ILLUMINATION
Authors: Charman W. N.
Published: November 2011

SYNOPSIS

This paper discusses the relationship between the diffraction images formed by reflecting objects under axial incident illumination and those of transparent objects in axial transmitted illumination. Experiments to measure the diffraction images produced by the incident illumination of circular absorbing holes in an opaque reflecting film of aluminium are described; the results are compared with those reported earlier for the images of opaque disks of the same diameter illuminated by transmitted light. The differences between the two types of images are discussed, together with their effect on visual measurements.
THE ULTRASTRUCTURAL LOCALIZATION OF PHOSPHATASES IN THE NEURONES OF THE SNAIL, HELIX ASPERSA
Authors: Meek G. A. , Lane Nancy J.
Published: November 2011

SYNOPSIS

The lipid droplets and other cell organelles in the cytoplasm of the neurones of the common snail, Helix aspersa, have been studied with the electron microscope: (1) after fixation in the conventional osmium tetroxide media, without incubation; (2) after incubation for the localization of thiamine pyrophosphatase (TPP‐ase) and inosinc diphosphatase (IDP‐ase) by Novikoff and Goldfischer's method (1961); and (3) after incubation for acid phosphatase according to the technique of Holt and Hicks (1961a, b). The three types of lipid droplet described by Chou and Meek (1958) are readily identifiable after all the procedures used, and so is the lamellar Golgi apparatus. It is therefore concluded that the ultrastructure of the Golgi apparatus cannot be an artifact of fixation. TPP‐ase and IDP‐ase activity are found in the lamellæ of the Golgi apparatus and in the phospholipid droplets; less activity is found in the mixed lipid droplets and none in the triglyceride droplets. This evidence indicates that there are certain similarities between the lamellæ of the Golgi complex and the membranes of the phospholipid droplets. High levels of acid phosphatase activity are present in the mixed lipid droplets; these may therefore be the morphological counterparts in Helix neurones of the “lysosomes” defined biochemically by de Duve (1959). Some acid phosphatase activity is also found in the phospholipid droplets, and in the lamellæ and vesicles of the Golgi apparatus. The mixed lipid droplets appear to contain triglyceride inclusions, and it is suggested that their phospholipid content may be concerned with the metabolism or the transfer of neutral lipids in the cell.
The size of bacteria, as measured by interference microscopy
Authors: ROSS K. F. A. , GALAVAZI G.
Published: November 2011

SYNOPSIS

Bacteria were examined with a Smith interference microscope using a half‐shade eyepiece and photomicrographs of their images were prepared. Microdensitometer traces on the negatives demonstrated conclusively that the method developed by Ross in 1957 to measure the thickness of bacteria was subject to systematic error. This error was eliminated by modifying the half‐shade eyepiece so that its comparison area was no larger than the image of a single bacterium; a critical comparison of this new method of measurement of phase change through small microscopic objects demonstrated its advantages over the other well‐established methods.

Measurements of bacterial thickness obtained by this new method are markedly lower than those obtained by other interferometric methods; they are, however, still slightly higher (by a maximum of 30 p.c.) than the values obtained by measuring the widths of similar bacteria directly from the mid‐points of the diffraction fringes visible at the boundaries of the image. The work of Wolter and of Charman is discussed in the light of these findings.
Silver iodate techniques for the histological demonstration of normal and pathological nervous tissue
Authors: DUCKETT SERGE , TRIGGS MARGARET
Published: November 2011

SYNOPSIS

Methods are described for staining cells of the nervous system using sodium and potassium iodate instead of the carbonate salts as used in the classical Hortega techniques. The methods are quick and easy, the rate of success high, and tissues which have been fixed for a long time in formol can be used.
Stereologic techniques in microscopy
Authors: FREERE R. H. , WEIBEL E. R.
Published: November 2011

SYNOPSIS

The principal measuring methods employed in morphometry, generally known as stereology, allow information on volumes, surface areas, numbers of structures, and many other dimensions to be derived from simple counting operations. Until relatively recently these techniques have found only limited application in biology, although they have been used for many years in the inorganic sciences. With the development of reliable quantitative methods in physiology and biochemistry, however, stereologic techniques are becoming increasingly important and a number of interesting methods have been developed which are both rapid and simple. In this paper a number of practical techniques are presented which have proved useful in light and electron microscopy.