bluuebunny/crossref_metadata_2025 huggingface dataset:
Microtubule flexibility, microtubule-based nucleation and ROP pattern co-alignment enhance protoxylem microtubule patterning
Authors: Jacobs Bas , Saltini Marco , Molenaar Jaap , Filion Laura , Deinum Eva E.
Published: January 2025

The development of the water transporting xylem tissue in plants involves an intricate interplay of Rho-of-Plants (ROP) proteins and cortical microtubules to generate highly functional secondary cell wall patterns, such as the ringed or spiral patterns in early-developing protoxylem. We study the requirements of protoxylem microtubule band formation with simulations in CorticalSim, extended to include finite microtubule persistence length and a novel algorithm for microtubule-based nucleation. We find that microtubule flexibility facilitates pattern formation for all realistic degrees of mismatch between array and pattern orientation. At the same time, flexibility leads to more density loss, both from collisions and the microtubule-hostile gap regions, making it harder to maintain microtubule bands. Microtubule-dependent nucleation helps to counteract this effect by gradually shifting nucleation from the gap regions to the bands as microtubules disappear from the gaps. Our results reveal mechanisms that can result in robust protoxylem band formation.
Methodological tests using Amazonian soil samples for 14C-AMS dating
Authors: Jou Renata M , Macario Kita D , Pessenda Luiz C , Gomes Fabiana B , Oliveira Fabiana M , Pedrosa Renan , Alves Eduardo Q , Fallon Stewart , Santos Leonardo J C , Maniesi Vanderlei , Bastos Alexis S
Published: January 2025

Although radiocarbon-accelerator mass spectrometry (14C-AMS) is an important tool for the establishment of soil chronology, its application is challenging due to the complex nature of soil samples. In the present study, chemical extraction methodologies were tested to obtain the most representative age of Amazonian soil deposition by 14C-AMS. We performed acid hydrolysis with different numbers of extractions, as well as treatments combining acid and bases and quartered and non-quartered samples. The ages of the soil organic matter (SOM) fractions were compared to the ages of naturally buried charcoal samples at similar depths. The results showed that the age of the non-hydrolyzable inert fraction of soil was closer to the age of charcoal and older than the ages of humin. It was also observed that the quartering process can influence the results, since the dating of the humin fraction showed variability in the results. Our results are important to provide information about the most suitable method for the 14C-AMS dating of soil samples for paleoenvironment reconstruction studies.
The Early Upper Paleolithic of Korea: A chronological review
Authors: Seong Chuntaek , Chong Donghee
Published: January 2025

Despite the continuous reporting of radiometric chronology of lithic assemblages in the Korean peninsula, systematic evaluation of reliable radiocarbon (14C) dates and discussion on the lithic technological variability have not been adequately presented. This paper attempts to address the issue reviewing the available data on the Early Upper Paleolithic (EUP) of Korea, with a focus on 14C chronology and lithic technology. Also, these recent advances in Paleolithic studies in Korea provide interesting aspects of the transition to Upper Paleolithic (UP) technology in East Asia. The transition to the UP is characterized by two key developments: the emergence of blade technology and tanged points, and the use of quality raw material that had been previously disregarded. Reliable 14C dates published recently indicate that this transition began around 43,000–40,000 cal BP. We propose that the emergence of the UP tradition on the Korean peninsula can be explained by focusing on the mobility, regional exchange networks and population dynamics of hunter-gatherers rather than the continuing resort to the simple unidirectional dispersal.
Kostant’s problem for parabolic Verma modules
Authors: Mazorchuk Volodymyr , Srivastava Shraddha
Published: January 2025

We give a complete combinatorial classification of the parabolic Verma modules in the principal block of the parabolic category

$\mathcal{O}$

associated with a minimal or a maximal parabolic subalgebra of the special linear Lie algebra for which the answer to Kostant’s problem is positive.
The House of Baha’u’llah and the Struggle for Religious Visibility in Mandatory Iraq
Authors: Cooper-Davies Christopher
Published: January 2025

This article analyses the struggle for possession of the House of Baha’u’llah in Baghdad during the 1920s and 1930s. One of the Bahai religion’s most sacred sites, the House of Baha’u’llah was the subject of protracted legal and political-diplomatic disputes following efforts by anti-Bahai activists to appropriate it from its Bahai custodians in 1921. The ensuing case touched almost every facet of the Iraqi judicial system, galvanised the international Bahai community and captured the attention of the British colonial state, the Iraqi government and the League of Nations. This article explores the causes and implications of the dispute, which can be considered one of the first incidents of religious persecution in modern Iraq. Rather than explaining the incident with reference to the intolerant attitudes of the Shi`i majority, the article argues for the role of the institutions of colonial modernity – the Mandates system, the new minorities regime, the praxis and discourse of colonial expansion, and the internationalism of the interwar period – for the unravelling of the case itself and for affecting modern, secular articulations of anti-Bahai prejudice.
All Progressives Congress v Bashir Sheriff and Others: The Conflict Between Legal Technicalities and Justice
Authors: Nwodo Fochi Amabilis , Anya Sylvester Ndubuisi , Chime Ikechukwu , Amucheazi Chibike Oraeto
Published: January 2025

One of the issues for determination in All Progressives Congress v Bashir Sheriff and Others was whether the first respondent won the primary election that was conducted according to the Electoral Act 2022. This issue, however, was not addressed because the Supreme Court set aside the suit because the first respondent failed to initiate it through the proper originating process. This decision contrasts with its previous judgment in Ekanem v The Registered Trustees of the Church of Christ the Good Shepherd, where it held that an inappropriate originating process does not undermine the competence of a suit. By departing from this previous decision, this note argues that there is a high possibility that the Supreme Court may have aided in the subversion of the Constitution. It recommends that the Electoral Act 2022 be amended to restrict the court's authority to dismiss election disputes if they were initiated through inappropriate originating processes.
Collisionless zonal-flow dynamics in quasisymmetric stellarators
Authors: Zhu Hongxuan , Lin Z. , Bhattacharjee A.
Published: January 2025

The linear collisionless plasma response to a zonal-density perturbation in quasisymmetric stellarators is studied, including the geodesic-acoustic-mode oscillations and the Rosenbluth–Hinton residual flow. While the geodesic-acoustic-mode oscillations in quasiaxisymmetric configurations are similar to tokamaks, they become non-existent in quasi-helically symmetric configurations when the effective safety factor in helical-angle coordinates is small. Compared with concentric-circular tokamaks, the Rosenbluth–Hinton residual is also found to be multiplied by a geometric factor

$\mathcal {C}$

that arises from the flux-surface-averaged classical polarization. Using the near-axis-expansion framework, we derive an analytic expression for

$\mathcal {C}$

, which varies significantly among different configurations. These analytic results are compared with numerical simulation results from the global gyrokinetic particle-in-cell code GTC, and good agreement with the theoretical Rosenbluth–Hinton residual level is achieved when the quasisymmetry error is small enough.
Pinus sylvestris bark extract reduces the impact of Heligmosomoides bakeri infection on C57BL/6 but not on BALB/c mice (Mus musculus)
Authors: Blomstrand Berit Marie , Thamsborg Stig Milan , Steinshamn Håvard , Enemark Heidi Larsen , Aasen Inga Marie , Mahnert Karl-Christian , Sørheim Kristin Marie , Shepherd Francesca , Houdijk Jos , Athanasiadou Spiridoula
Published: January 2025

Plant secondary metabolites (PSMs) may improve gastrointestinal health by exerting immunomodulatory, anti-inflammatory and/or antiparasitic effects. Bark extracts from coniferous tree species have previously been shown to reduce the burden of a range of parasite species in the gastrointestinal tract, with condensed tannins as the potential active compounds. In the present study, the impact of an acetone extract of pine bark (Pinus sylvestris) on the resistance, performance and tolerance of genetically diverse mice (Mus musculus) was assessed. Mice able to clear an infection quickly (fast responders, BALB/c) or slowly (slow responders, C57BL/6) were infected orally with 200 infective third-stage larvae (L3) of the parasitic nematode Heligmosomoides bakeri or remained uninfected (dosed with water only). Each infection group of mice was gavaged for 3 consecutive days from day 19 post-infection with either bark extract or dimethyl sulphoxide (5%) as vehicle control. Oral administration of pine bark extract did not have an impact on any of the measured parasitological parameter. It did, however, have a positive impact on the performance of infected, slow-responder mice, through an increase in body weight (BW) and carcase weight and reduced feed intake by BW ratio. Importantly, bark extract administration had a negative impact on the fast responders, by reducing their ability to mediate the impact of parasitism through reducing their performance and tolerance. The results indicate that the impact of PSMs on parasitized hosts is affected by host's genetic susceptibility, with susceptible hosts benefiting more from bark extract administration compared to resistant ones.
The law of thaw: understanding subnational land use policies for permafrost-agroecosystems
Authors: Parlato Nicholas J. , Ward Jones Melissa
Published: January 2025

As the Arctic warms and growing seasons start to lengthen, governments and producers are speculating about northern “climate-driven agricultural frontiers” as a potential solution to food insecurity. One of the central ecological factors in northern spaces, however, is permafrost (perennial frozen ground), which can drive cascading environmental changes upon thaw. Considering the land requirements for expanded agriculture and the unique challenges of northern farming, national and subnational governments are grappling with and facilitating this speculative boom in different ways. Analysing agricultural land use policy instruments from the US State of Alaska and the Republic of Sakha (Yakutia) in Russia, this paper investigates if and how permafrost factors into their legal frameworks and what impacts this has on agricultural development, conservation, and food security. Alaska and the Republic of Sakha were chosen for reasons including both having at least 100 years of agricultural history on permafrost soils, both containing extensive amounts of permafrost within their landmasses and both containing permafrost that is ice-rich. Comparing legal texts as indicative of state capacities and strategies to govern, the paper finds that the two regions diverge in how they understand and regulate permafrost, and suggests that these approaches could benefit from one another. Bringing together geoclimatic and sociocultural concerns to problematise static policy divisions, this paper gestures to a path forward wherein subnational policy can balance needs for food, environmental, and cultural security in the North.
Anglo-Romano Common Law on Natural Subjecthood, Lansdowne MS 486 ff. 142–143
Authors: Dudani N. R. W.
Published: January 2025

Together Cæsar and Cotton left an immense trove of English state papers on all matters of subjects. While Cæsar spent much of his lifetime as an officer of state, e.g., Master of the Rolls, they both devised innumerable works of great value. For instance, both he and Cotton expounded upon the issue of the post-nati and other arguments made in the conferences on the union with Scotland in Parliament. With their cessation in 1607, Cæsar undertook his most significant follow-up work: “That neither any General Statute nor Nativity only make a Man (whose Parents were Strangers) to be a Natural Subject in any Country.” Later duplicated by Cotton in Titus, F. IV., the intricacies of its two pages remained long-guarded in the private possession of such great men as Lords, Secretaries of State, and Prime Ministers. Only two centuries after Cæsar commenced its work did it come full circle to the British Museum—itself, ironically, formed from the seized library of Cotton. As for legal precedent, it is unique in that its broad historical scope predated the complexities of England's permanent royal colonies in America. During this period, every regnant—except for Charles I and James II—would assent unto major naturalization or alien statutes during their reign, all of which remained common law throughout England, the Empire, and America until, at the least, 1863.
Synthetic users: insights from designers’ interactions with persona-based chatbots
Authors: Gu (Eric) Heng , Chandrasegaran Senthil , Lloyd Peter
Published: January 2025

Personas are hypothetical representations of real-world people used as storytelling tools to help designers identify the goals, constraints, and scenarios of particular user groups. A well-constructed persona can provide enough detail to trigger recognition and empathy while leaving room for varying interpretations of users. While a traditional persona is a static representation of a potential user group, a chatbot representation of a persona is dynamic, in that it allows designers to “converse with” the representation. Such representations are further augmented by the use of large language models (LLMs), displaying more human-like characteristics such as emotions, priorities, and values. In this paper, we introduce the term “Synthetic User” to describe such representations of personas that are informed by traditional data and augmented by synthetic data. We study the effect of one example of such a Synthetic User – embodied as a chatbot – on the designers’ process, outcome, and their perception of the persona using a between-subjects study comparing it to a traditional persona summary. While designers showed comparable diversity in the ideas that emerged from both conditions, we find in the Synthetic User condition a greater variation in how designers perceive the persona’s attributes. We also find that the Synthetic User allows novel interactions such as seeking feedback and testing assumptions. We make suggestions for balancing consistency and variation in Synthetic User performance and propose guidelines for future development.
The Worse than Nothing Account of Harm: A Fallen Hero
Authors: Johansson Jens , Risberg Olle
Published: January 2025

Daniel Immerman has recently put forward a novel account of harm, the Worse than Nothing Account. We argue that this account faces fatal problems in cases in which an agent performs several simultaneous actions. We also argue that our criticism is considerably more powerful than another one that has recently been advanced.
On perfect subdivision tilings
Authors: Lee Hyunwoo
Published: January 2025

For a given graph

$H$

, we say that a graph

$G$

has a perfect

$H$

-subdivision tiling if

$G$

contains a collection of vertex-disjoint subdivisions of

$H$

covering all vertices of

$G.$

Let

$\delta _{\mathrm {sub}}(n, H)$

be the smallest integer

$k$

such that any

$n$

-vertex graph

$G$

with minimum degree at least

$k$

has a perfect

$H$

-subdivision tiling. For every graph

$H$

, we asymptotically determined the value of

$\delta _{\mathrm {sub}}(n, H)$

. More precisely, for every graph

$H$

with at least one edge, there is an integer

$\mathrm {hcf}_{\xi }(H)$

and a constant

$1 \lt \xi ^*(H)\leq 2$

that can be explicitly determined by structural properties of

$H$

such that

$\delta _{\mathrm {sub}}(n, H) = \left (1 - \frac {1}{\xi ^*(H)} + o(1) \right )n$

holds for all

$n$

and

$H$

unless

$\mathrm {hcf}_{\xi }(H) = 2$

and

$n$

is odd. When

$\mathrm {hcf}_{\xi }(H) = 2$

and

$n$

is odd, then we show that

$\delta _{\mathrm {sub}}(n, H) = \left (\frac {1}{2} + o(1) \right )n$

.
New approaches to the architectural design, amenities, and function of macella: typologies, scale, and the Macellum Magnum
Authors: Hanson J. W.
Published: January 2025

In recent years, scholars have drawn particular attention to the existence in the ancient world of permanent, specialized market buildings, macella or μάκɛλλοι, which offered dedicated facilities for the processing and sale of luxury commodities such as fish and meat. However, important questions remain about the typologies, architecture, and “end-users” of these structures. Here, I outline a basic model for how the total and average wealth and traffic of settlements increases with estimated populations, before exploring the relationships between the total footprints and wider architectural characteristics of macella and estimated populations of sites. This reveals that there is a series of relationships between these measures that are not only consistent with wider theoretical and empirical expectations, but also have the potential to alter dramatically our understanding of macella by revealing the connections between the sizes and capacities of these structures and the wealth, connectivity, and integration of settlements.
Human Intelligence: Sex Differences
Authors: Jarvik Lissy F.
Published: January 2025

An extensive review of the literature on sex differences in human intelligence leads to the conclusion that there is strong evidence for sex differences in processing both verbal and spatial information. The few genetic studies that there are all point toward a sex-linked mode of inheritance of certain spatial abilities.
Biochemical and Genetic Variables Associated with Mothers of G1-Trisomy Affected Children
Authors: Kerkay Julius , Zsako Steven , Cotton James E. , Kaplan Arnold R.
Published: January 2025

The significant differences in biochemical and chromosomal characteristics, and familial history observed between group of mothers who gave birth to children affected with G1-trisomy (Down's syndrome) and their age-matched controls, indicate that these three maternal variables, in addition to the well known variable of maternal age, are associated with etiology of the aneuploidy. Since attempts to find statistical correlation between these chromosomal and biochemical variables failed, it is believed that these three are unrelated, but very possible etiological factors.
Possible Role of the Cytoplasm in the Course of Morphogenesis, Namely, in the Case of Twinning
Authors: Giroud A.
Published: January 2025

A number of facts that cannot be interpreted in terms of nuclear genes would seem to be interpretable in terms of cytoplasmic heredity. The hereditary role of the mitochondria has already been demonstrated in molds. The role of the cytoplasm (matrilineal heredity) has also been shown in some phanerogams, and analogous facts have been noted in insects and molluscs. In amphibians, the influence of an alteration of the egg cortical cytoplasm has been shown to reappear in the following generations. This cortical cytoplasm includes the morphological plan of the organism with its bilateral symmetry: mirror imaging in monozygotic twins would only be an extension of bilateral symmetry. In Tatusia novemcincta the twins may be morphologically or chemically different, which may only be explained by an unequal subdivision of a heterogenic cytoplasm. Similar facts are observed in human twinning. Monozygotic twins are usually discordant with respect to congenital malformations (especially symmelia and anencephaly), which may only be interpreted in terms of unequal distribution of cytoplasmic properties.
Abnormal Umbilical Vessels and Systemic Circulatory Reversal in Thoracopagus Twins
Authors: Chaurasia B.D.
Published: January 2025

A human thoracopagus of slightly unequal twins having a common umbilical cord with exomphalos is described, with special reference to the cardiovascular system. The larger twin had single umbilical artery. The smaller twin had a large left umbilical artery which was in direct continuity with the aorta, a small right umbilical artery with sole connection to the right external and internal iliac arteries (right common iliac artery was absent), missing umbilical vein, a rudimentary nonfunctional heart with atresia of the truncus arteriosus, and a right-sided aortic arch. Exomphalos of both twins is accounted by the possible defective growth of umbilical mesoderm caused by abnormal umbilical vessels. Reversal of systemic circulation in the upper part of the body of smaller twin is discussed. The importance of a careful study of umbilical veins is emphasized.
Clastogenic Effect of TrenimonR on in Vitro Chromosomes of Phenotypically Healthy Subjects with Morphologically Abnormal Caryotype
Authors: Meist Hannes
Published: January 2025

The effect of a given concentration of TrenimonR (6 × 20−8 mol/1) on the lymphocytes of 11 healthy subjects with morphologically abnormal karyotype was analysed in vitro. The research included 6 subjects with balanced translocations, one of them with a centric fusion. Of the remaining 5 subjects, 2 had a duplication in the paracentric region, 1 showed an inversion, and 2 had a marker chromosome.

In the group with morphologically abnormal chromosomes a higher sensibility to the influence of TrenimonR was found as compared with a control group with morphologically normal karyotype. The subjects with an atypical karyotype had 36 to 65% aberrations, the control group 28%. A localization of the breaks showed no increased aberration rates in the morphologically abnormal chromosomes.
Genetic Counseling in Congenital Deafness
Authors: François J. , Bie S. De , Leuven M.Th. Matton-Van
Published: January 2025

The risk of having a child affected by isolated congenital deafness (or deafmutism) is high, if the two parents are affected, if only one parent is affected, but belonging to an affected family, and if the couple has already an affected child.
Trisomy 2q
Authors: Dallapiccola B. , Forabosco A. , Calabro A.
Published: January 2025

Two unrelated patients with trisomy 2q32 → q37, resulting from maternal balanced translocations t(2; 13) (q32 q33) and t(2; 15) (q32 q26) are reported. Comparison of the clinical findings suggests that trisomy 2q is associated with a rather characteristic constellation of symptoms and malformations.
A Case of “G 2 Deletion Syndrome”: Ring or Partial Monosomy? (46,XX,22r or 46,XX,22p- ?)
Authors: Milani-Comparetti M. , Rossolini V. , Pace D.P. , Burroni M. , Magistrelli R. , Saccucci F.
Published: January 2025

A case of “G 2 Deletion Syndrome” is reported, based on concordant cytogenetic, clinical and dermatoglyphic findings. The definition of the syndrome, as associated with either a ring or a partially deleted chromosome 22, is discussed. The resulting interpretation favours the hypothesis of deletion of the short arm extending into the centromere.
Modified Method of C Banding Using Barium Hydroxide
Authors: Ghosh P.K. , Singh Indera P.
Published: January 2025

A modified centromeric heterochromatin banding technique using barium hydroxide octahydrate is described. The relationship between slide maturity and time of denaturation by barium-hydroxide is discussed.
Correlation Matrices for Palmar Dermatoglyphic Traits in Twins
Authors: Sharma A. , Guha A.
Published: January 2025

Intraclass correlation values have been studied in a sample of 50 MZ and 50 DZ twins with respect to fourteen palmar dermatoglyphic metric traits in binary combinations. The results confirm the general trends already shown in singleton studies. The shape of the palmar surface does not appear to be significantly correlated with other metric traits. Generally speaking, a large independence has been found between the various traits.
Inclination of Longitudinal Axis of Palmarprint with Intertriradial Distance a-d, PMPC, and DWC
Authors: Sharma A. , Sapra P. , Mainigi K.
Published: January 2025

The wide fluctuations of the three angular measurements, a-d, PMPC, and DWC with longitudinal axis make palmar projective breadth (PB) the ideal standard axis for any work involving the quantitative estimates of longitudinal and transverse trends of palmar triradii.
Inheritance of a Peculiar Type of Hypodontia
Authors: Mitter Navnit S.
Published: January 2025

A peculiar type of hypodontia is described in two opposite sexed siblings and considered to be inherited as an autosomal recessive trait
Twining in India
Authors: Goswami H.K. , Wagh K.V.
Published: January 2025

The incidence of twinning in India, as estimated on the basis of data from the various types of maternity centers, so as to include both urban and rural population, appears to be 15.97 per thousand (12.6 DZ, 3.3 MZ). The incidence is significantly higher in rural than urban populations (18.1 vs. 11.8 per thousand). It is suggested that this may be accompanied with a higher production of DZ, possibly opposite-sexed twins.
Twins in Nature, Science, and Society
Authors: Gedda Luigi
Published: January 2025

Signor Presidente della Repubblica Italiana,

Signor Sindaco,

Signor Ministro,

Eccellenza Rev.ma,

Signori Ambasciatori,

Signor Preside della Facoltà Medica dell'Università di Roma,

Onorevoli Autorità, Congressisti di 30 Nazioni, Gemelli e Amici dei Gemelli,

Nel settembre del 1953 veniva inaugurato in Roma l'Istituto di Genetica Medica e di Gemellologia Gregorio Mendel.

Per i vent'anni dell'Istituto Mendel abbiamo aperto la celebrazione con il Congresso Internazionale di Neurogenetica ed ora la chiudiamo con il Primo Congresso Internazionale di Studi Gemellari. La Neurogenetica come specializzazione della Genetica Medica e gli Studi Gemellari come espressione scientifica della Gemellologia inquadrano bene il significato del lavoro che l'Istituto Mendel va sviluppando, e la vostra presenza, cosí autorevole, significativa e cordiale, dona il più ambito coronamento civico, scientifico e umano al ricordo della nostra fondazione.

Noi vi ringraziamo con semplicità ma con schiettezza e rispettosamente ringrazio il Capo dello Stato per il prestigio della sua carica e della sua persona, ed anche perché proviene da una regione italiana, la Campania, che batte il record per la frequenza dei gemelli nella popolazione (25‰). Come ringrazio sentitamente il Sindaco che ci permette di aprire il Congresso in Campidoglio, luogo che ha il potere, come nessun altro al mondo, di evocare e sublimare quella singolare condizione umana che consiste nella gemellità: l'essere gemelli. Qui vi è la lupa che dà il suo latte ai gemelli dimostrando che la fiera è pietosa più della donna che espone i suoi figli alla morte. Qui sono Romolo e Remo che il mito esalta come fondatori di città, Romolo di Roma e Remo di Siena.
Twins in Myth
Authors: Rachewiltz B. De , Parisi P. , Castellani V.
Published: January 2025

Twins have an important place in mythology and a sacred character appears to be attached to them since the most ancient times. In ancient Egypt, the royal placenta was worshipped, being considered as the Pharao's twin (a conception that is still alive among certain African populations), and actually everyone was considered to possess a spiritual twin, the Ka or astral body, through whom it was supposed to be possible to operate with magic rituals and hit enemies. Twin gods were worshipped by Babylonians and Assyrians (who even introduced them among astronomic constellations), and may be also found in the Persian and Veda religions. In the classic, Greco-Roman world, the examples of twin gods and heroes are innumerable: from the twin sons of Zeus, the Dioscuri, to the opposite-sexed twin gods Apollo and Diana, to Rome's founders, Romulus and Remus, etc. Since the most ancient times, a magic conception is connected to the twins, either in a positive or a negative sense, but often with some kind of a “fatidic” aspect. Such a two-faced approach to the phenomenon of twinning, that variously characterizes neareast, protomediterranean, classic, and other ancient civilizations, may still be found in contemporary primitive societies.
Attitudes Towards Twinning in Primitive Societies
Authors: Leroy F.
Published: January 2025

In primitive societies twinning raises emotions varying from extreme terror to hope and joy. The first impulse prevailing among the less civilized people seems to be to regard twins as unnatural and monstrous and therefore as portending evil. Accordingly, they must be put to death and the offence repudiated. This negative attitude stems from a series of explanations which can generally be connected with the widespread belief in superfetation and double paternity. In a few cases only, would the custom of sacrificing twins arise from economic necessities. However, in many agricultural primitive tribes, twinning is regarded as a happy event. In this case, the worship of twins entrusts them namely with power over water allowing to confer fertility to the soil and also to women and animals. In the past, the mother of twins was often executed with her offspring or simply banished. In many tribes, she is still compelled to go through elaborate purification in order to forestall the evil omen. If twins are welcomed, their parents are similarly respected as they symbolize the fertility power of the clan. Superstitions and myths pertaining to twinning are universal and often present converging features among cultures without mutual contact. This would point to the twin cult as one of the earliest religious beliefs of mankind.
Is Weinberg's Method Valid?
Authors: Bulmer M.G.
Published: January 2025

Suppose that L like-sexed and U unlike-sexed twins have been observed. Weinberg's method estimates the numbers of DZ andMZ twins as DZ = 2U and MZ = L—U. This method is based on the assumptions that (1) the sex ratio in DZ twins is 1/2 and (2) the sexes of DZ twins are determined independently and with the same probability in all parents; in consequence there should, on average, be equal numbers of like-sexed and unlike-sexed DZ twins. The first assumption is not exactly true, but the necessary correction is negligible. Departures from the second assumption would probably lead to an excess of like-sexed over unlike-sexed DZ twins; in consequence, Weinberg's method would underestimate the numbers of DZ twins and overestimate the numbers of MZ twins. The literature on the frequencies of like-sexed and unlike-sexed pairs among twins known to be DZ through other genetic markers is reviewed. It is concluded that there is no evidence of an excess of like-sexed twins among them, and that there is therefore no reason to doubt the validity of Weinberg's method. The extension of Weinberg's method to estimate the zygosity types of triplets and quadruplets is described; it is shown that the resulting estimates agree well with the results of direct zygosity determination by blood grouping.
Retrospective Studies on the Twinning Rate in Scandinavia
Authors: Eriksson A.W. , Eskola M.R. , Fellman J.O.
Published: January 2025

The rates of human multiple maternities in the Nordic countries were studied from continuous series of data. In the Åland and Åboland archipelagos the parish records for births and baptisms since the 1650's were used. Various sources, some unpublished, in the archives of statistics were used for Sweden (since 1749) and Finland (since 1859) as a whole. Until recently, the rates of multizygotic multiple maternities in isolated island populations in the Åland and Åboland archipelagos have been some of the highest known among Whites (15-20‰). Highly significant temporal fluctuations in the twinning rates were noted. In Sweden, the twinning rate during the last part of 18th century was about twice as high as it was in 1966-70. The triplet and quadruplet rates were about three to four times as high as they are nowadays. There has been a secular decline in DZ twinning. This downward trend set in first in the isolated populations. In Sweden, it started in the 1930's, but in Finland, not until the 1960's. The steep downward trend in the twinning rates is shown to set in about one generation after the break-up of isolation. This can be interpreted as evidence that the changes in matrimonial migration patterns have affected the rates of DZ twinning.
Biology of the Twinning Phenomenon: Embryogenesis and Teratogenesis
Authors: Lutz Hubert
Published: January 2025

The twinning phenomenon has always interested the great public, the artists, and naturally the scientists. Isidore Geoffroy St. Hilaire has established a classification still now valid. This classification considers the different types of double monsters which are found in nature in all classes of vertebrates, including man. To explain the twinning phenomenon, the experimental realizations have progressed by successive bounds after the preliminary attempts of different authors. Now, when it is question of experimental duplication, anybody thinks of Speman for the amphibians, of Lutz for the birds, of Seidel for the rabbit, and of Tarkowsky for the mouse. Now, it is possible to conceive a twinning resulting from the separation of the first blastomeres (amphibian, rabbit, mouse) and a twinning originating from the fissuration of the blastoderm (bird, mammal). All these experiments confirm the unicist-theory. If a total or partial regulation of the excedents may be experimentally realized, no argument can however support this theory in the realization of the double monstrosity.
Monozygotic Heterocaryotic Twinning
Authors: Lejeune J. , Aurias A.
Published: January 2025

Since the first publication in 1961, cases of monozygotic heterocaryotic twinning have been repeatedly found and a total of 14 observations can now be analysed. The mechanism involved in this type of twinning is yet uncertain and eventually is not identical in each case, the main uncertainty being to decide whether the chromosomal error affecting one of the twins is related, directly or indirectly, to the process of MZ twinning per se. Regarding the time of occurrence, the error seems to occur at few days of development at the most and, in one case at least, was contemporary to the first division cleavage. Considering the possibility of twins of different sex (e.g., one XY and one XO) the MZ heterocaryotic twinning could be considered as a potential equivalent of autofecundation in species in which the XO is a fertile female. Evolutive implications shall be discussed.
A Case of Conjoined Twins
Authors: Myrianthopoulos Ntinos C. , de la Burdé Brigitte
Published: January 2025

Among 56,249 maternities in the Collaborative Perinatal Project, 615 were twin maternities. One of these resulted in stillborn thoracoomphalopagus MZ female twins with multiple cardiovascular, alimentary and other malformations. The case is of further interst in that the mother had a surgically removed brain tumor in childhood and exhibited neurological symptoms and bizarre behavior before and during pregnancy. Drugs and treatments which she received during pregnancy are not known to be teratogenic.
Monoamniotic Twins
Authors: Foglmann Ragna
Published: January 2025

Six new cases of monoamniotic twins are reported. All had true knots of the cord, the result being double survival in 5 cases and 11 normal children. The mechanism of twin development is described and monoamniotic twins are placed in accordance with the two theories from the literature. A short review of both the Scandinavian and the world cases is presented.
Familial Twinning: A Case for Superfetation in Man
Authors: Rhine S.A. , Nance Walter E.
Published: January 2025

A family is described in which the tendency to bear twins is expressed in the offspring of males as well as females. All of the twins born in this family show marked discordance in birth weight and gestational age. In 5 of the 6 pairs, one twin was normal while the other was either a macerated fetal mass, stillborn, or died of prematurity in the neonatal period. The one pair in which both twins did survive is known to be DZ and showed a difference in maturity and a 21% discrepancy in birth weight. Thus, twinning in this family appears to be transmitted as an autosomal dominant trait which is expressed in the offspring of both female and male carriers. Of all possible genetic mechanisms which could explain this familial aggregation of markedly discordant twins, supcrfetation seems most consistent with the genetic transmission and expression of the trait in the offspring of both males and females. The most plausible explanation of the pedigree is that a dominant gene is segregating in the family which is expressed in the fetal placenta where it acts to reverse the normal hormonal inhibition of ovulation. Since both the father and the mother contribute to the genotype of the placenta, superfeiation could occur among offspring of both males and females who carry the gene.
Triplet Pregnancy in a Subfertile Woman Treated with Clomiphene Citrate
Authors: Pezzani M.
Published: January 2025

A 26-year-old subfertile woman with a history of abortions at the 7-9th week was treated with Clomid, 50 mg for 5 days. A pregnancy resulted, which ended in the premature birth of a set of alive triplets that sex and blood-group determinations showed to be trizygotic. It is suggested that this production of a multiple ovulation in a woman with luteal deficiency be the result of excessive dosage of Clomid.
The Problem of Genotype-Environment Correlation in the Estimation of Heritability from Monozygotic and Dizygotic Twins
Authors: Jensen Arthur R.
Published: January 2025

It is commonly, but incorrectly, assumed that the presence of genotype × environment covariance must necessarily reduce the heritability (h2) as estimated from twin data, when the formula used to obtain h2 makes no assumption about G × E covariance or assumes that it is zero. But, in fact, G × E covariance does not always reduce the genetic variance, and it can be shown under some conditions, an increase in the G × E covariance implies a greater genetic variance. The effect of G × E covariance on h2 as estimated from data on MZ and DZ twins, depends jointly upon the degree of assortative mating and the degree of environmental correlation between MZ twins and between DZ twins. A method, based on the solution of a pair of simultaneous quadratic equations, is proposed for estimating the range of h2 from twin data under varying assumed values for assortative mating, the environmental correlations between MZ and DZ twins, and the G × E covariance. The solution of three simultaneous equations permits direct estimation of the genetic variance, environmental variance, and G × E covariance, under varying reasonable assumed values for assortative mating and the MZ and DZ environmental correlations. Examples of the method are based on intelligence tests scores of MZ and DZ twins.
Analysis of Twin Data and Estimation of Heritability Effects
Authors: Wilson Ronald S.
Published: January 2025

In a statistical sense, the objective of twin research is to partition the variance on some criterion measure among genetic and environmental factors. Although certain elaborate models have been developed, these models do not supply a convenient test statistic to show which factors make a significant contribution. Consequently several procedures drawn from analysis of variance have been adapted for use with twin data.
Genetic Studies of the Offspring of Identical Twins - A Model for the Analysis of Quantitative Inheritance in Man
Authors: Nance Walter E.
Published: January 2025

In conjunction with full-sib and parental observations, half-sib analysis permits an estimation of the genetic and environmental variance as well as a partitioning of the genetic variance into its additive, dominance and epistatic components. The offspring of identical twins are a unique class of human half-sibs who provide an unusual opportunity to resolve and measure several additional potentially important sources of human variation including maternal effects, the influences of common environmental factors and assortative mating.

The genetic model thus developed for the analysis of quantitative inheritance in man has been applied to the analysis of total ridge count and birth weight, confirming the existence of a major additive genetic effect on ridge count and a significant maternal effect on birth weight.
Alcohol Consumption in Relation to Factors Associated with Ischemic Heart Disease - A Cotwin Control Study
Authors: Myrhed Marten , Floderus Birgitta
Published: January 2025

Moderately alcohol-discordant male twin pairs, aged 45-65 years, have been examined with respect to ischemic heart disease (IHD) and associated factors. No conclusion can yet be drawn with regard to manifest or subclinical IHD, while significant disparities were found with regard to systolic and diastolic blood pressures, high cigarette consumption, hyperglycemia, and serum cholesterol; the greater number of findings of pathological values were found in the high alcohol-consumption as compared to the low alcohol-consumption cotwins. These findings offer a possible explanation for the increased number of reports showing a connection between high consumption of alcohol and occurrence of ischemic heart disease.
A Monozygotic Cotwin Control Study of a Treatment for Myopia
Authors: Schwartz J. Theodore
Published: January 2025

Myopia is the world's most common cause of defective vision. The role of controlled accommodation on the progress of myopia is unsettled. This cotwin control study is designed to provide a careful appraisal of the effectiveness of a clinically acceptable method of controlling accommodation. There are no previous reports of similar prospective studies among MZ twins. Expansion of such studies would be aided by collaboration among interested investigators.
Genetics of Plasma Cholesterol and Triglycerides: A Study of Adult Male Twins
Authors: Christian Joe C. , Feinleib Manning , Hulley Stephen B. , Castelli William P. , Fabsitz Richard R. , Garrison Robert J. , Borhani Nemat O. , Rosenman Ray H. , Wagner John
Published: January 2025

Fasting plasma triglycerides and cholesterol, as well as cholesterol in very low density, low density and high density lipoproteins, were measured in 250 MZ and 264 DZ adult male twin pairs. A new method was used to choose an estimate of genetic variance. This includes an estimate of genetic variance for use when the total variances of MZ and DZ twins are unequal. DZ twins had greater total variance for cholesterol. When genetic variance was estimated by subtracting the within-MZ-sets mean square from the within-DZ-sets mean square, all of the lipids had significant estimates of genetic variance; however, when genetic variance was estimated by a method designed to correct bias due to unequal total variances of MZ and DZ twins, only triglycerides had significant genetic variance. The heritability of plasma triglycerides was calculated to be 0.68.
Plasma Protein Variability in MZ Twins
Authors: Milani-Comparetti M. , Saccucci F.
Published: January 2025

A previous study had shown that only MZ twins are easily exchanged by trained police dogs. This is certainly due to the superimposability of the biochemical basis of body scent. A different approach has now been tried, based on plasma protein fractionating procedures. A pilot study has shown that PolyAcrilamide Gel Electrophoresis (PAGE) results, as expected, in widely different patterns only in DZ twin pairs. Plasma specimens from a sample of 55 supposedly MZ twin pairs were analysed by PAGE. The substantial superimposability of MZ cotwin patterns was confirmed. Analysis of the different fractions indicates the extent of environmental variability. Application to zygosity determination is suggested.
Genetic Basis of Individual Differences in Tissue Composition
Authors: Ohtsuki T. , Klissouras V.
Published: January 2025

A total of 10 pairs of twin adolescent boys, 14 MZ and 5 DZ, were used to determine the relative contribution of the genotype to the individual differences observed in surface density of muscle, subcutaneous fat, and bone. The cross-sectional areas of these tissue components were calculated from photographs of the upper arm, taken by means of an ultrasonic apparatus. The respective mean percentage intrapair difference in MZ and DZ twins was 6.9 and 9.8 for total area, 6.6 and 7.8 for muscle, 13.9 and 32.0 for fat, and 6.7 and 31.3 for bone tissue. Interindividual variations in bone only could be ascribed to genetic differences.
Distribution of Blood Groups, Salivary Blood Group Substances, and Natural Antibodies in a Sample of MZ Twins
Authors: Pace D.P. , Saccucci F. , Britti F. , Casini D.
Published: January 2025

The distribution of A1A2BO, MN, and Rh-Hr blood groups, of salivary ABH substances, and of natural antibodies, was assessed in a sample of 47 MZ twin pairs. The resulting distribution provides indications as to the level of genetic control over the quantitative expression of these traits.
Heritability Study on Size of the Physiologic Cup of the Optic Nerve Head - A Summary Report
Authors: Schwartz J. T. , Reuling F. H. , Feinleib M.
Published: January 2025

Cupping of the optic nerve head is regarded as one of a triad of diagnostic signs associated with glaucoma. This study was undertaken to assess the role of genetic factors in determining size of the physiologic cup of the normal optic nerve head, as measured by a horizontal cup/disc ratio. This is important to our ultimate understanding of the determinants of pathologic change. Horizontal cup/disc ratio was estimated in a sample of 37 MZ and 26 like-sex DZ twin pairs aged 15 years and older. Differences between MZ and DZ samples with respect to intrapair variance and intraclass correlation coefficient were highly significant. This finding of high heritability for measurements of cup diameter is in contrast to low heritability estimates found in a companion investigation on heritability of the effect of corticosteroids on intraocular pressure.
Twin Studies and Behavior Genetics
Authors: Jarvik Lissy F.
Published: January 2025

It is observed that neither the methodology of twin studies nor that of behavior genetics in general has been adequately explored in most investigations of human behavior. General distrust of genetic methodologies as well as the belief that genie disorders are unalterable appear to be salient factors in explaining the neglect of those areas by social scientists. A plea is made for putting aside biased attitudes that prevent utilization of the best available techniques for the study of human beings as distinguished from all other animals.
Nature-Nurture and Intelligence: The Twin and Adoption Studies Agree
Authors: Horn Joseph M. , Loehlin John C. , Willerman Lee
Published: January 2025

A large-scale adoption study is underway at the University of Texas where IQ test scores are available for over 1200 women who gave up their children for adoption immediately following delivery. The adopted children and their adoptive families are now being located and tested and, if current trends continue, complete data should eventually be available on over 400 families. About half of these families will contain two or more adopted children or both adopted and natural children. At present, data are available for 89 families. The results are consistent with twin data and support a genetic hypothesis. The biological mother-adopted child correlation is 0.37 whereas the adoptive mother-adopted child and adoptive father-adopted child correlations are only 0.22 and 0.04 respectively. There are 59 pairs of unrelated children reared together in this sample and the IQ correlation for these children is only 0.13.