Changes In Relative Size Research Articles

Occupational Percentile Rank: A New Method for Constructing a Socioeconomic Index of Occupational Status

In this paper, we propose a method for constructing an occupation-based socioeconomic index that can easily incorporate changes in occupational structure. The resulting index is the occupational percentile rank for a given cohort, based on contemporaneous information pertaining to educational composition and the number of workers at the occupation level. An occupation may experience an increase or decrease in its occupational rank due to changes in relative sizes and educational compositions across occupations. The method is flexible in dealing with changes in occupational and educational measurements over time. Applying the method to U.S. history from the mid-nineteenth century to the present day, we derive the index using IPUMS U.S. Census microdata from 1850 to 2000 and the American Community Surveys (ACSs) from 2001 to 2018. Compared to previous occupational measures, this new measure takes into account occupational status evolvement caused by long-term secular changes in occupational size and educational composition. The resulting percentile rank measure can be easily merged with social surveys and administrative data that include occupational measures based on the U.S. Census occupation codes and crosswalks.

The pupil of the camera-like eyes of terrestrial gastropod mollusks (Heterobranchia, Stylom-matophora)

In terrestrial pulmonate gastropods Cochlodina laminata, Monachoides incarnata, Helicigona lapicida, Arianta arbustorum, Cepaea hortensis, Trochulus hispidus and Succinea putris, the morphological properties of the pupil of camera-like eyes were studied for the first time: location, spatial orientation, change in spatial orientation, structure, shape, shape change, relative size, change in relative size. Several methods were used in the work: making of preparations of isolated eyes, making of histological preparations of eyes, light microscopy, morphometric analysis, statistical analysis, calculations. All the studied morphological properties of the pupil of the camera-like eyes of C. laminata, M. incarnata, H. lapicida, A. arbustorum, C. hortensis and T. hispidus are similar to the analogous morphological properties of the pupil of the camera-like eyes of other species of terrestrial pulmonates. One of the studied morphological properties of the pupil of the camera-like eye of S. putris – the relative size – differs from the analogous morphological property of the pupil of the camera-like eyes of other species of terrestrial pulmonates.

Aerial photogrammetry of seabirds from digital aerial video images using relative change in size to estimate flight height

Aerial photogrammetry of seabirds from digital aerial video images using relative change in size to estimate flight height

Convergence is Only Skin Deep: Craniofacial Evolution in Electric Fishes from South America and Africa (Apteronotidae and Mormyridae).

SynopsisApteronotidae and Mormyridae are species-rich clades of weakly electric fishes from Neotropical and Afrotropical freshwaters, respectively, known for their high morphological disparity and often regarded as a classic example of convergent evolution. Here, we use CT-imaging and 3D geometric morphometrics to quantify disparity in craniofacial morphologies, and to test the hypothesis of convergent skull-shape evolution in a phylogenetic context. For this study, we examined 391 specimens representing 78 species of Apteronotidae and Mormyridae including 30 of 37 (81%) of all valid genera with the goal to sample most of the craniofacial disparity known in these clades. We found no overlap between Apteronotidae and Mormyridae in the skull-shape morphospace using PCA and a common landmark scheme, and therefore no instances of complete phenotypic convergence. Instead, we found multiple potential instances of incomplete convergence, and at least one parallel shift among electric fish clades. The greatest components of shape variance in both families are the same as observed for most vertebrate clades: heterocephaly (i.e., opposite changes in relative sizes of the snout and braincase regions of the skull), and heterorhynchy (i.e., dorsoventral changes in relative snout flexion and mouth position). Mormyrid species examined here exhibit less craniofacial disparity than do apteronotids, potentially due to constraints associated with a larger brain size, ecological constraints related to food-type availability. Patterns of craniofacial evolution in these two clades depict a complex story of phenotypic divergence and convergence in which certain superficial similarities of external morphology obscure deeper osteological and presumably developmental differences of skull form and function. Among apteronotid and mormyrid electric fishes, craniofacial convergence is only skin deep.

Efficacy of Oral Doxycycline in Reducing the Size of Pterygium lesions

Objective: To assess the efficacy of oral Doxycycline in reducing the size of pterygium lesions in a Pakistani population
 Study Design: Quasi-experimental study.
 Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi, from Sep 2018 and May 2019.
 Methodology: Sixty patients above 20 years of age were enrolled in the study. Oral Doxycycline 200m/day was given for thirty consecutive days. Photographs of the lesions were taken at the time of recruitment and at the end of the study for assessment of pterygium size. Difference between pre-treatment and post-treatment size was analysed and comparison was made with age, gender and initial lesion size.
 Results: Twenty-two females and thirty-eight males were examined. The mean age of the participants was 48.8 ± 13.8 years. The mean size of the pterygium lesions before commencing the treatment was 12.24 ± 6.28 mm2. The mean size of the lesions after the treatment was 11.24 ± 5.39 mm2. The mean difference size was 1.00 ± 1.62 mm2 (p <0.001). The relative change in size (i.e. post-treatment size divided by pre-treatment size) was 0.94 ± 0.09 which was found to be statistically significant (p<0.001). There was correlation between larger initial lesion size and greater relative reduction in size (r = -0.42, p = 0.001).
 Conclusion: The change in the size of pterygium lesions produced by Doxycycline was found to be statistically significant but was not deemed clinically significant. Therefore, oral Doxycycline is not recommended for the treatment of pterygium in our population.

Time-resolved absolute radius estimation of vibrating contrast microbubbles using an acoustical camera.

Ultrasound (US) contrast agents consist of microbubbles ranging from 1 to 10 μm in size. The acoustical response of individual microbubbles can be studied with high-frame-rate optics or an "acoustical camera" (AC). The AC measures the relative microbubble oscillation while the optical camera measures the absolute oscillation. In this article, the capabilities of the AC are extended to measure the absolute oscillations. In the AC setup, microbubbles are insonified with a high- (25 MHz) and low-frequency US wave (1-2.5 MHz). Other than the amplitude modulation (AM) from the relative size change of the microbubble (employed in Renaud, Bosch, van der Steen, and de Jong (2012a). "An 'acoustical camera' for in vitro characterization of contrast agent microbubble vibrations," Appl. Phys. Lett. 100(10), 101911, the high-frequency response from individual vibrating microbubbles contains a phase modulation (PM) from the microbubble wall displacement, which is the extension described here. The ratio of PM and AM is used to determine the absolute radius, R0. To test this sizing, the size distributions of two monodisperse microbubble populations ( R = 2.1 and 3.5 μm) acquired with the AC were matched to the distribution acquired with a Coulter counter. As a result of measuring the absolute size of the microbubbles, this "extended AC" can capture the full radial dynamics of single freely floating microbubbles with a throughput of hundreds of microbubbles per hour.

Tumour Size and T-Stage in Pancreatic Cancer Resection Specimens Depend on the Pathology Examination Approach.

Simple SummaryTumour size is considered a key oncological feature, as it reflects the primary tumour burden. In pancreatic cancer, tumour size also constitutes the defining criterion for staging of the primary tumour (T-stage), which provides essential information for patient treatment, risk stratification in clinical trials and cancer registries. While measurement of tumour size in pancreatic cancer resection specimens is considered accurate and reproducible, this has not been formally proven. This study investigated whether, and in how far, various approaches to tumour size measurement result in different tumour sizes and consequently different T-stages. The study findings show that tumour size and T-stage are different in a significant proportion of cases, depending on whether (i) the tumour was measured in one or two planes and (ii) the macroscopic tumour size was corroborated microscopically. Hence, a divergence in pathology practice may limit the comparability of tumour size and T-stage between institutions.In the eighth edition of the TNM classification for pancreatic ductal adenocarcinoma (PDAC), stages T1 to T3 are defined by tumour size, size measurement being deemed objective and accurate. This study investigated whether various, currently used approaches to tumour measurement result in different tumour sizes and differences in T-stage assignment. In a series of 315 resected PDAC, tumour sizes were measured as follows: macroscopically in a single or in two perpendicular planes and with or without microscopic corroboration. Comparison of the resulting tumour sizes showed that both macroscopic measurement in two planes and microscopic corroboration gave significantly different results (p < 0.001). Compared to the most simple approach (macroscopic measurement in one plane), the comprehensive approach (macroscopic measurement in two planes with microscopic corroboration) resulted in a larger tumour size in 263 (83%) cases (mean absolute size difference: 10 mm; mean relative size change: 36%). T-stage assignment differed in 142 (45%) cases between the simple and comprehensive approach and affected 87%, 38% and 48% of the cases deemed to be stage T1, T2 and T3, respectively. In conclusion, tumour size and T-stage are highly approach-dependent. Consensus on an accurate method is required to ensure comparability of these basic data.

A deep learning-based hybrid artificial intelligence model for the detection and severity assessment of vitiligo lesions

BackgroundWe aimed to establish and validate a deep learning-based hybrid artificial intelligence (AI) model for the objective morphometric and colorimetric assessment of vitiligo lesions.MethodsTwo main datasets containing curated images of vitiligo lesions from Chinese patients (Fitzpatrick skin types III or IV) were established, including one with 2,720 images for lesion localization study and the other with 1,262 images for lesion segmentation study. Besides, an additional test set containing 145 images of vitiligo lesions from other Fitzpatrick skin types (I, II, or V) was also generated. A 3-stage hybrid model was constructed. YOLO v3 (You Only Look Once, v3) architecture was trained and validated to classify and localize vitiligo lesions, with sensitivity and error rate as primary performance outcomes. Then a segmentation study comparing 3 deep convolutional neural networks (DCNNs), Pyramid Scene Parsing Network (PSPNet), UNet, and UNet++, was carried out based on the Jaccard index (JI). The architecture with the best performance was integrated into the model. Three add-on metrics, namely VAreaA, VAreaR, and VColor were finally developed to measure absolute, relative size changes and pigmentation, respectively. Agreement between the AI model and dermatologist evaluators were assessed.ResultsThe sensitivity of the YOLO v3 architecture to detect vitiligo lesions was 92.91% with an error rate of 14.98%. The UNet++ architecture outperformed the others in the segmentation study (JI, 0.79) and was integrated into the model. On the additional test set, however, the model achieved a lower detection sensitivity (72.41%) and a lower segmentation score (JI, 0.69). With respect to size changes, no difference was observed between the AI model, trained dermatologists (W=0.812, P<0.05), and Photoshop analysis (P=0.075, P=0.212 respectively), which all displayed good concordance.ConclusionsWe developed a novel, convenient, objective, and quantitative deep learning-based hybrid model which simultaneously evaluated both morphometric and colorimetric vitiligo lesions from patients with Fitzpatrick skin types III or IV, rendering it suitable for the assessment of severity of vitiligo lesions in Asians in both clinic and research scenarios. More work is also warranted for its use in other ethnic skin groups.

Surface effect on two nanocracks emanating from an electrically semi-permeable regular 2n-polygon nanohole in one-dimensional hexagonal piezoelectric quasicrystals under anti-plane shear

In this paper, the conformal mapping from a regular 2[Formula: see text]-polygon hole with two collinear asymmetric cracks into a circle is constructed. Based on the Gurtin–Murdoch surface/ interface model and complex potential theory, two collinear asymmetric nanocracks emanating from an electrically semi-permeable regular 2[Formula: see text]-polygon nanohole embedded in an infinite one-dimensional hexagonal piezoelectric quasicrystals with surface effect are investigated. The size-dependent stress intensity factors of phonon field and phason field, electric displacement intensity factor at the nanocrack tip are derived for electrically semi-permeable boundary condition. Numerical examples are illustrated to show that the size of the hole, mechanical load, electric load, cracks relative size change with stress intensity factor of phonon field and electric displacement intensity factor. Also analyzed the change of the electric displacement intensity factor with different electric permeability at the nanocrack tip and the dimensionless intensity factor with [Formula: see text].

Comparative anatomy of dissected optic lobes, optic ventricles, midbrain tectum, collicular ventricles, and aqueduct: evolutionary modifications as potential explanation for non-tumoral aqueductal anomalies in humans

PurposeAn extensive literature has postulated multiple etiologies for aqueductal stenosis. No publications were found, discussing that evolutionary modifications might explain aqueductal anomalies. This study’s objectives were to review the evolutionary modifications of vertebrates’ tectum structures that might explain human aqueduct anomalies. Undertaking vertebrate comparative study is currently not feasible in view of limitations in obtaining vertebrate material. Thus, vertebrate material collected, injected, dissected, and radiographed in the early 1970s was analyzed, focusing on the aqueduct and components of the midbrain tectum.MethodsPhotographs of brain dissections and radiographs of the cerebral ventricles and arteries of adult shark, frog, iguana, rabbit, cat, dog, and primate specimens, containing a barium-gelatin radiopaque compound, were analyzed focusing on the aqueduct, the optic ventricles, the quadrigeminal plate, and collicular ventricles. The anatomic information provided by the dissections and radiographs is not reproducible by any other radiopaque contrast currently available.ResultsDissected and radiographed cerebral ventricular and arterial systems of the vertebrates demonstrated midbrain tectum changes, including relative size modifications of the mammalian components of the tectum, simultaneously with the enlargement of the occipital lobe. There is a transformation of pre-mammalian optic ventricles to what appear to be collicular ventricles in mammals, as the aqueduct and collicular ventricle form a continuous cavity.ConclusionsThe mammalian tectum undergoes an evolutionary cephalization process consisting of relative size changes of the midbrain tectum structures. This is associated with enlargement of the occipital lobe, as part of overall neocortical expansion. Potentially, aqueductal anomalies could be explained by evolutionary modifications.

Preparation of 2D coatings of functionally graded chitosan-gold nanocomposite through in-situ reduction in cationic and anionic environments: Application for inhibiting hepatocellular carcinoma cells response

Time-dependent assessment for the formation of gold nanoparticles (GNP) within chitosan (CS) matrix and their relative change in size and distribution was examined by monitoring the in-situ reduction of metal ions. UV–Vis spectroscopic analysis confirmed obtainability of GNP with tunable size, density and functionality which conversed from binomial to monomial distribution function of size at an increased concentration of CS. Uniform distribution of ~7 nm nanoparticles was confirmed by TEM image analysis of polymer-metal composites at optimum conditions. XRD analysis of chitosan-gold (CS-GNP) composite coatings confirmed the presence of gold nanoparticles having two (111) and (200) crystal planes. Energy dispersive X-ray spectroscopy and 1H NMR were carried out to confirm the incorporation and uniform distribution of GNP within the composite. The reduction of gold chloride by chitosan was successively achieved in both acidic (cationic environment) and basic pH (anionic environment). A relative change in the % transmittance at peaks attributing to amine group (1579 cm−1) and hydroxyl group (3405 cm−1) was observed in the FTIR spectra of CS-GNP indicating the role of these groups in reduction process at different pH environments. These functionally graded films showed decreased viability and proliferation of human hepatocellular carcinoma cells (HepG2) at in-vitro conditions.

Resonant Pulsing Frequency Effect for Much Smaller Bubble Formation with Fluidic Oscillation

Microbubbles have several applications in gas-liquid contacting operations. Conventional production of microbubbles is energetically unfavourable since surface energy required to generate the bubbles is inversely proportional to the size of the bubble generated. Fluidic oscillators have demonstrated a size decrease for a system with high throughput and low energetics but the achievable bubble size is limited due to coalescence. The hypothesis of this paper is that this limitation can be overcome by modifying bubble formation dynamics mediated by oscillatory flow. Frequency and amplitude are two easily controlled factors in oscillatory flow. The bubble can be formed at the displacement phase of the frequency cycle if the amplitude is sufficient to detach the bubble. If the frequency is too low, the conventional steady flow detachment mechanism occurs instead; if the frequency is too high, the bubbles coalesce. Our hypothesis proposes the existence of a resonant mode or ‘sweet-spot’ condition, via frequency modulation and increase in amplitude, to reduce coalescence and produce smallest bubble size with no additional energy input. This condition is identified for an exemplar system showing relative size changes, and a bubble size reduction from 650 µm for steady flow, to 120 µm for oscillatory-flow, and 60 µm for resonant condition (volume average) and 250 µm for steady-flow, 15 µm for oscillatory-flow, 7 µm for the resonant condition. A 10-fold reduction in bubble size with minimal increase in associated energetics results in a substantial reduction in energy requirements for all processes involving gas-liquid operations. The reduction in the energetic footprint of this method has widespread ramifications in all gas-liquid contacting operations including but not limited to wastewater aeration, desalination, flotation separation operations, and other operations.

Effect of different protein supply on growth of three populations of a crab adapted to low energy diets

Juvenile individuals of the crab Neohelice granulata (Brachyura: Grapsoidea: Varunidae) were grown in laboratory using five artificial diets containing 3, 6, 12, 18 and 24 % of crude protein and 3 % of lipids during 7 months. Crabs belonged to three different populations. Two of them, San Antonio Oeste (SAO) and Riacho San Jose (RSJ) are close; they are not genetically differentiated but vary in morphological traits. The third, Mar Chiquita (MC), is far and genetically differentiated from the other two, but morphological traits of their individuals are intermediate. The growth (absolute and relative size change, final body mass), molting frequency, hepatosomatic index of individuals, as well as the Carbon and Nitrogen content and histological structure of their digestive glands, were analyzed. Mar Chiquita individuals differed from one or both of the other two populations. Time to first molt was significantly longer in MC, final size was significantly smaller in MC than RSJ and hepatosomatic index was significantly lower in MC compared to SAO and RSJ. San Antonio Oeste and RSJ individuals never differed. Furthermore, in all cases crabs were able to molt and growth with all diets, although growth in size and mass were higher, and intermolt periods shorter, when diets contained higher percentages of protein. It is concluded that species is well adapted to low quality food sources and it is suggested that size differences previously observed between SAO and RSJ crabs are due to phenotypic plasticity, while differences with MC population are governed by evolutionary adaptation to different food availability.

Mini Tightrope Fixation Versus Ligament Reconstruction – Tendon Interposition for Maintenance of Post-trapeziectomy Space Height: A Biomechanical Study

To test the biomechanical stability of ligament reconstruction and tendon interposition (LRTI) compared with Mini TightRope fixation for thumb metacarpal subsidence after trapeziectomy. Fifteen fresh human cadaveric hands underwent trapeziectomy and were divided into 3 treatment groups: LRTI using a biotenodesis screw and single versus dual Mini TightRope fixation. The thumb and index fingers were removed distal to the metacarpal; the distal ends of the metacarpals and proximal radius were potted in urethane resin and mounted onto a servohydraulic testing machine. A cyclic axial load was applied to stress the trapezial cavity. We recorded displacement of the first metacarpal via the position of the actuator head and computed the size of the trapezial space as the difference of the initial size and first metacarpal displacement. Each specimen underwent cyclical loading until the first metacarpal had collapsed completely onto the scaphoid (failure of the repair) or until 6 hours of testing had been completed. The number of cycles to failure, change in the size of the trapezium cavity, and relative change in size of the trapezium cavity were determined. The trapezial space had completely closed before 6 hours of testing were completed in all biotenodesis screw-augmented LRTI specimens and remained present in all single and dual Mini TightRope specimens. Absolute (and normalized) changes in the size of the trapezial cavity in the single and dual Mini TightRope specimens were 11 ± 2 and 10 ± 2 mm, respectively. Dual Mini TightRope fixation provided superior load bearing and maintenance of trapezial space height compared with single Mini TightRope or LRTI biotenodesis screw procedures. This study demonstrates that patients who undergo suture suspension arthroplasty may be able to move earlier because of the immediate stability the construct affords.

Postnatal craniofacial ontogeny in neandertals and modern humans

Neandertals and humans are closely related but differ noticeably in adult morphology. Previous work has been equivocal as to the contribution of postnatal growth and development to these differences. Due to disparate preservation, most analyses focus on specific anatomies, reconstructed fossils, or limited sample sizes. The objective of this research is to highlight the importance of postnatal growth in expressing Neandertal-human distinctions in the craniofacial skeleton, using a large and unreconstructed Neandertal sample. A resampling approach is utilized to compare relative size change in 20 craniofacial dimensions between Neandertals (n = 42) and humans (n = 262). The large number of immature Neandertal samples within and between dental stages provides the necessary variation to test for growth differences. Nested resampling using human-human comparisons assesses the likelihood of observing human-Neandertal growth differences under the null hypothesis of similar ontogenetic variation. Humans and Neandertals undergo comparable levels of overall size change. However, we identify growth differences for a number of traits, helping explain some of the unique features of this fossil taxon. Nested resampling shows it is unlikely that a Neandertal-like maturation would be observed in a random ontogenetic sample of humans. Growth during adolescence appears to be fundamental in the expression of some Neandertal anatomies. Neandertal upper facial and nasal breadths appear to have expanded rapidly after puberty to account for differences between preadolescents and adults, and Neandertals and humans. Mandibular growth differences may relate to anterior tooth use to process foods and paramastication during Neandertal maturation.

Modes of ontogenetic allometric shifts in crocodylian vertebrae

During postnatal ontogeny of vertebrates, allometric trends in certain morphological units or dimensions can shift drastically among isometry, positive allometry, and negative allometry. However, detailed patterns of allometric transitions in certain timings have not been explored well. Identifying the presence and nature of allometric shifts is essential for understanding the patterns of changes in relative size and shape and the proximal factors that are controlling these changes mechanistically. Allometric trends in 10 selected vertebrae (cervical 2–caudal 2) from hatchlings to very mature individuals of Alligator mississippiensis (Archosauria, Crocodylia) are reported in the present study. Allometric coefficients in 12 vertebral dimensions are calculated and compared relative to total body length, including centrum, neural spine, transverse process, zygapophysis, and neural pedicle. During the postnatal growth, positive allometry is the most common type of relative change (10 of the 12 dimensions), although the diameter of the neural canal shows a negative allometric trend. However, when using spurious breaks (i.e. allometric trends subdivided into growth stages using certain growth events, and key body sizes and/or ages), vertebral parts exhibit various pathways of allometric shifts. Based on allometric trends in three spurious breaks, separated by the end of endochondral ossification (body length: approximnately 0.9 m), sexual maturity (1.8 m), and the stoppage of body size increase (2.8 m), six types of ontogenetic allometric shifts are established. Allometric shifts exhibit a wide range from positive allometry restricted only in the early postnatal stage (Type I) to life-long positive allometry (Type VI). This model of ontogenetic allometric shifts is then applied to interpret potential mechanisms (causes) of allometric changes, such as (1) growth itself (when allometric trend gradually decreases to isometric or negative allometric change: Type II–IV allometric shift); (2) developmental constraint (when positive allometry is limited only in the early growth stage: Type I allometric shift); and (3) functional or biomechanical drive (when positive allometry continues throughout ontogeny: Type VI allometric shift).

Morphological plasticity in the Aristotle’s lantern of Arbacia dufresnii (Phymosomatoida: Arbaciidae) off the Patagonian coast.

The relative size of the Aristotle’s lantern of most sea urchins varies in relation to the food availability and it is often used to infer the availability of food of the environment. The aim of our study was to evaluate the lantern morphology plasticity of Arbacia dufresnii in populations with different environmental characteristics, either mussel beds or disturbed areas, by the invasive alga Undaria pinnatifida along the Patagonian Atlantic coast. The test diameter of the sea urchins along with the weight and height of the lanterns, the jaw lenght and rotula lenght were measured. Classic and geometric morphometric analyses were performed to test differences among populations. The length of the jaw was the best indicator of relative changes in size of the lantern. The largest length of the jaw was measured in individuals from disturbed areas dominated by the invasive algae U. pinnatifida. The rotula shape changed with the increase of the diameter of the sea urchins, it tends to be more elongated with larger sea urchins.

Infinitely Adaptive Transition Metal Oxychalcogenides: The Modulated Structures of Ce2O2MnSe2 and (Ce0.78La0.22)2O2MnSe2

This article reports the syntheses, structures, and physical properties of the oxychalcogenides (Ce1–xLax)2O2MnSe2 with x = 0–0.7. These materials have a layered structure related to that of the LaOFeAs-derived superconductors but with the transition metal sites 50% occupied. Ce2O2MnSe2 contains alternating layers of composition: [Ce2O2]2+ and [MnSe2]2–. The size mismatch between the layers leads to an incommensurate structure with a modulation vector of q = αa*+ 0b*+0.5c* with α = 0.158(1), which can be described with a (3 + 1)D superspace structural model in superspace group Cmme(α,0,1/2)0s0 [67.12]. There is a strong modulation of Mn site occupancies, leading to a mixture of corner- and edge-sharing MnSe4/2 tetrahedra in the [MnSe2]2– layers. The modulation vector can be controlled by partial substitution of Ce3+ for larger La3+, and a simple commensurate case was obtained for (Ce0.78La0.22)2O2MnSe2 with α = 1/6. The materials respond to the change in relative size of the oxide and chalcogenide blocks by varying the ratio of corner- to edge-sharing tetrahedra. The superspace model lets us unify the structural description of the five different ordering patterns reported to date for different Ln2O2MSe2 (Ln = lanthanide) materials. Mn moments in Ce2O2MnSe2 and (Ce0.78La0.22)2O2MnSe2 order antiferromagnetically below TN = 150 K, and Ce moments order below ∼70 K. The magnetic structures of both materials have been determined using neutron diffraction. Both materials are semiconductors; Ce2O2MnSe2 has σ = 9 × 10–6 Ω–1 cm–1 at room temperature and an activation energy for charge carrier mobility from RT to 170 °C of ∼0.4 eV.

Dynamics in a Mature Industry: Entry, Exit, and Growth of Big‐Box Grocery Retailers

This paper measures market dynamics within the U.S. grocery industry (defined as supermarket, supercenter, and club retailers). We find that despite being a mature industry, the grocery industry is remarkably dynamic. Each year retailers open or close roughly 7% of U.S. stores. We also find significant changes in the size of firms’ operations within markets over time. These changes in relative size are largely the result of expansion or contraction by incumbents rather than the result of firm entry or exit. In fact, entry and exit are quite rare, except by small firms. Moreover, only in small markets do new entrants gain substantial market share.

Late development of metric part-relational processing in object recognition.

Four experiments with unfamiliar objects examined the remarkably late consolidation of part-relational relative to part-based object recognition (Jüttner, Wakui, Petters, Kaur, & Davidoff, 2013). Our results indicate a particularly protracted developmental trajectory for the processing of metric part relations. Schoolchildren aged 7 to 14 years and adults were tested in 3-Alternative-Forced-Choice tasks to judge the correct appearance of upright and inverted newly learned multipart objects that had been manipulated in terms of individual parts or part relations. Experiment 1 showed that even the youngest tested children were close to adult levels of performance for recognizing categorical changes of individual parts and relative part position. By contrast, Experiment 2 demonstrated that performance for detecting metric changes of relative part position was distinctly reduced in young children compared with recognizing metric changes of individual parts, and did not approach the latter until 11 to 12 years. A similar developmental dissociation was observed in Experiment 3, which contrasted the detection of metric relative-size changes and metric part changes. Experiment 4 showed that manipulations of metric size that were perceived as part (rather than part-relational) changes eliminated this dissociation. Implications for theories of object recognition and similarities to the development of face perception are discussed.