Facialmetric similarities mediate mate choice: sexual imprinting on opposite-sex parents

Former studies have suggested that imprinting-like processes influence the shaping of human mate preferences. In this study, we provide more direct evidence for assessing facial resemblance between subjects' partner and subjects' parents. Fourteen facial proportions were measured on 312 adults belonging to 52 families, and the correlations between family members were compared with those of pairs randomly selected from the population. Spouses proved to be assortatively mated in the majority of measured facial proportions. Significant correlations have been found between the young men and their partner's father (but not his mother), especially on facial proportions belonging to the central area of the face. Women also showed resemblance to their partner's mother (but not to their father) in the facial characteristics of their lower face. Replicating our previous studies, facial photographs of participants were also matched by independent judges who ascribed higher resemblance between partners, and subjects and their partners' opposite-sex parents, compared with controls. Our results support the sexual imprinting hypothesis which states that children shape a mental template of their opposite-sex parents and search for a partner who resembles that perceptual schema. The fact that only the facial metrics of opposite-sex parents showed resemblance to the partner's face tends to rule out the role of familiarity in shaping mating preferences. Our findings also reject several other rival hypotheses. The adaptive value of imprinting-related human mating is discussed, and a hypothesis is made of why different facial areas are involved in males' and females' search for resemblance.     

A new OH5 reconstruction with an assessment of its uncertainty

The OH5 cranium, holotype of Paranthropus boisei consists of two main portions that do not fit together: the extensively reconstructed face and a portion of the neurocranium. A physical reconstruction of the cranium was carried out by Tobias in 1967, who did not discuss problems related to deformation, although he noted a slight functional asymmetry. Nevertheless, the reconstructed cranium shows some anomalies, mainly due to the right skewed position of the upper calvariofacial fragment and uncertainty of the relative position of the neurocranium to the face, which hamper further quantitative analysis of OH5′s cranial geometry. Here, we present a complete virtual reconstruction of OH5, using three-dimensional (3D) digital data, geometric morphometric (GM) methods and computer-aided design (CAD) techniques. Starting from a CT scan of Tobias’s reconstruction, a semi-automatic segmentation method was used to remove Tobias’s plaster. The upper calvariofacial fragment was separated from the lower facial fragment and re-aligned using superposition of their independent midsagittal planes in a range of feasible positions. The missing parts of the right hemiface were reconstructed using non-uniform rational basis-spline (NURBS) surface and subsequently mirrored using the midsagittal plane to arrive at a symmetrical facial reconstruction. A symmetric neurocranium was obtained as the average of the original shape and its mirrored version. The alignment between the two symmetric shapes (face and neurocranium) used their independent midsagittal plane and a reference shape (KNM-ER 406) to highly reduce their degrees of freedom. From the series of alternative reconstructions, we selected the middle of this rather small feasible range. When reconstructed as a range in this way, the whole cranial form of this unique specimen can be further quantified by comparative coordinate-based methods such as GM or can be used for finite element modeling (FEM) explorations of hypotheses about the mechanics of early hominin feeding and diets.     

Facial resemblance increases the attractiveness of same-sex faces more than other-sex faces

Our reactions to facial self-resemblance could reflect either specialized responses to cues of kinship or by-products of the general perceptual mechanisms of face encoding and mere exposure. The adaptive hypothesis predicts differences in reactions to self-resemblance in mating and prosocial contexts, while the by-product hypothesis does not. Using face images that were digitally transformed to resemble participants, I showed that the effects of resemblance on attractiveness judgements depended on both the sex of the judge and the sex of the face being judged: facial resemblance increased attractiveness judgements of same-sex faces more than other-sex faces, despite the use of identical procedures to manipulate resemblance. A control experiment indicated these effects were caused neither by lower resemblance of other-sex faces than same-sex faces, nor by an increased perception of averageness or familiarity of same-sex faces due to prototyping or mere exposure affecting only same-sex faces. The differential impact of self-resemblance on our perception of same-sex and other-sex faces supports the hypothesis that humans use facial resemblance as a cue of kinship.     

山顶洞101号男性头骨的三维颅面复原

山顶洞101号头骨化石是东亚地区保存最为完整的化石之一,是探讨东亚地区现代人起源的重要研究材料。本文依据数据集中现生人的面部软组织平均分布,提出了计算机三维颅面复原方法,实现了101号头骨生前面貌的预测复原。主要包括三个步骤：首先使用CT完成了101号男性头骨和下颌骨仿制模型的三维重建。然后,利用计算机技术将现生人的面部软组织分布作为101号头骨的面部软组织分布,实现了颅面虚拟复原,并采用手工绘画技巧再现了复原面貌的形态特征。最后,提出了一种基于面部软组织分布和面貌统计形状模型的形态分析方法,实现了颅面复原结果的评估。山顶洞101号头骨的复原面貌具有头部较长、额头前倾、眉弓粗壮等特征,与101号头骨的几何形态基本一致。该技术再现了更新世晚期人类的脑颅及面部的形态特征,为古人类颅面复原的研究提供了技术支持和参考资料。     

Is Beauty in the Face of the Beholder?

Opposing forces influence assortative mating so that one seeks a similar mate while at the same time avoiding inbreeding with close relatives. Thus, mate choice may be a balancing of phenotypic similarity and dissimilarity between partners. In the present study, we assessed the role of resemblance to Self’s facial traits in judgments of physical attractiveness. Participants chose the most attractive face image of their romantic partner among several variants, where the faces were morphed so as to include only 22% of another face. Participants distinctly preferred a “Self-based morph” (i.e., their partner’s face with a small amount of Self’s face blended into it) to other morphed images. The Self-based morph was also preferred to the morph of their partner’s face blended with the partner’s same-sex “prototype”, although the latter face was (“objectively”) judged more attractive by other individuals. When ranking morphs differing in level of amalgamation (i.e., 11% vs. 22% vs. 33%) of another face, the 22% was chosen consistently as the preferred morph and, in particular, when Self was blended in the partner’s face. A forced-choice signal-detection paradigm showed that the effect of self-resemblance operated at an unconscious level, since the same participants were unable to detect the presence of their own faces in the above morphs. We concluded that individuals, if given the opportunity, seek to promote “positive assortment” for Self’s phenotype, especially when the level of similarity approaches an optimal point that is similar to Self without causing a conscious acknowledgment of the similarity.     

Clinical examples of 3D dose distribution reconstruction,based on the actual MLC leaves movement,for dynamic treatment techniques

AimTo present practical examples of our new algorithm for reconstruction of 3D dose distribution, based on the actual MLC leaf movement.BackgroundDynaLog and RTplan files were used by DDcon software to prepare a new RTplan file for dose distribution reconstruction.Materials and methodsFour different clinically relevant scenarios were used to assess the feasibility of the proposed new approach: (1) Reconstruction of whole treatment sessions for prostate cancer; (2) Reconstruction of IMRT verification treatment plan; (3) Dose reconstruction in breast cancer; (4) Reconstruction of interrupted arc and complementary plan for an interrupted VMAT treatment session of prostate cancer. The applied reconstruction method was validated by comparing reconstructed and measured fluence maps. For all statistical analysis, the U Mann–Whitney test was used.ResultsIn the first two and the fourth cases, there were no statistically significant differences between the planned and reconstructed dose distribution (p = 0.910, p = 0.975, p = 0.893, respectively). In the third case the differences were statistically significant (p = 0.015). Treatment plan had to be reconstructed.ConclusionDeveloped dose distribution reconstruction algorithm presents a very useful QA tool. It provides means for 3D dose distribution verification in patient volume and allows to evaluate the influence of actual MLC leaf motion on the dose distribution.     

Early definitive bone and soft-tissue reconstruction of major gunshot wounds of the face

The use of craniofacial surgical techniques, extended open reduction, rigid fixation with plates and screws, and the replacement of severely damaged or missing bone with immediate bone grafting in the treatment of complex facial fractures has been applied to the management of severe gunshot wounds of the face. Early definitive bone and soft-tissue reconstruction has been performed in 37 patients. One-hundred and seventy-seven primary bone grafts were utilized in 33 patients for orbital, nasal, zygomatic, and maxillary reconstruction. Twenty-six patients required mandibular repair with compression or reconstruction plates. Soft-tissue reconstruction was provided by a combination of flaps. Four patients had extensive soft-tissue loss replaced by free vascularized omental flaps. The omentum provided circumferential coverage of the mandibular reconstruction and reconstruction of the floor of the mouth and was then tunneled in a circle through both cheeks into the middle and upper face. The omentum reconstructed deficits in the hard palate and upper buccal sulcus and was then wrapped around all zygomatic, orbital, and midfacial bone grafts and used to fill in dead space in the maxillary, ethmoid, and frontal sinuses. The omentum is not used to provide contour and bulk, but to cover bone grafts and plates and fill in dead space. Carefully shaped bone grafts provide the correct craniofacial scaffold. Early restoration of a midfacial bony scaffold and the prevention of soft-tissue contraction facilitate secondary reconstruction. Four late total nasal reconstructions with tissue-expanded forehead skin wrapped around bone grafts were performed.     

Detecting Genetic Association of Common Human Facial Morphological Variation Using High Density 3D Image Registration

Human facial morphology is a combination of many complex traits. Little is known about the genetic basis of common facial morphological variation. Existing association studies have largely used simple landmark-distances as surrogates for the complex morphological phenotypes of the face. However, this can result in decreased statistical power and unclear inference of shape changes. In this study, we applied a new image registration approach that automatically identified the salient landmarks and aligned the sample faces using high density pixel points. Based on this high density registration, three different phenotype data schemes were used to test the association between the common facial morphological variation and 10 candidate SNPs, and their performances were compared. The first scheme used traditional landmark-distances; the second relied on the geometric analysis of 15 landmarks and the third used geometric analysis of a dense registration of ∼30,000 3D points. We found that the two geometric approaches were highly consistent in their detection of morphological changes. The geometric method using dense registration further demonstrated superiority in the fine inference of shape changes and 3D face modeling. Several candidate SNPs showed potential associations with different facial features. In particular, one SNP, a known risk factor of non-syndromic cleft lips/palates, rs642961 in the IRF6 gene, was validated to strongly predict normal lip shape variation in female Han Chinese. This study further demonstrated that dense face registration may substantially improve the detection and characterization of genetic association in common facial variation.     

The performance of peat-filled subsurface flow filters treating landfill leachate and municipal wastewater

The main objective of this study was to determine the treatment capacity of well-mineralized peat in vertical and horizontal flow filters designed to reduce phosphorus, nitrogen and organic matter in municipal wastewater from the town of Tapa and landfill leachate in Väätsa, Estonia. Two identically designed onsite experiments were conducted using the following filter systems: (a) a vertical flow (VF) peat filter, (b) a vertical flow peat/ash sediment filter (both materials in equal volumes) followed by a horizontal flow (HF) peat filter. Sphagnum peat and hydrated oil-shale ash (ash sediment) was used. In our experiments, one treated municipal wastewater over 6 months and another treated landfill leachate over 12 months. In both cases, effluent from a conventional treatment (aerated activated sludge treatment) plant was used. The median value of total phosphorus (TP) concentration in Väätsa landfill leachate was 3.4 mg P L^?1 and in municipal wastewater from Tapa 4.9 mg P L^?1. The reduction of TP in VF peat filters during the first 6 months was 58% and 63%, and in peat/ash sediment filters 94% and 67% for the Tapa experiment and the Väätsa experiment, respectively. Both experiments demonstrated that the P-removal efficiency in VF peat filters begins to decrease after 6 months of operation. The purification efficiency in HF filters fluctuated, and no significant removal of TP was found. In the removal of organic matter (BOD, COD values) and nitrogen, the best results were obtained in VF peat filters.     

Does Facial Resemblance Enhance Cooperation?

Facial self-resemblance has been proposed to serve as a kinship cue that facilitates cooperation between kin. In the present study, facial resemblance was manipulated by morphing stimulus faces with the participants'' own faces or control faces (resulting in self-resemblant or other-resemblant composite faces). A norming study showed that the perceived degree of kinship was higher for the participants and the self-resemblant composite faces than for actual first-degree relatives. Effects of facial self-resemblance on trust and cooperation were tested in a paradigm that has proven to be sensitive to facial trustworthiness, facial likability, and facial expression. First, participants played a cooperation game in which the composite faces were shown. Then, likability ratings were assessed. In a source memory test, participants were required to identify old and new faces, and were asked to remember whether the faces belonged to cooperators or cheaters in the cooperation game. Old-new recognition was enhanced for self-resemblant faces in comparison to other-resemblant faces. However, facial self-resemblance had no effects on the degree of cooperation in the cooperation game, on the emotional evaluation of the faces as reflected in the likability judgments, and on the expectation that a face belonged to a cooperator rather than to a cheater. Therefore, the present results are clearly inconsistent with the assumption of an evolved kin recognition module built into the human face recognition system.     

The combined use of embryos and semen for cryogenic conservation of mammalian livestock genetic resources

The objective of this empirical simulation study was to evaluate the use of a combination of semen and embryos in the creation of gene banks for reconstruction of an extinct breed. Such an approach was compared for banks with varying proportions of embryos on the basis of the amount of the material to be stored, time for reconstruction, maintenance of genetic variability, and probability of failure during reconstruction. Four types of populations were simulated, based on reproductive rate: single offspring, twinning, enhanced reproduction, and litter bearing. Reconstruction was simulated for banks consisting of different combinations of semen and reduced numbers of embryos (expressed as a percentage of the material needed for a bank containing exclusively embryos and ranging from 10 to 90%). The use of a combination of semen and embryos increased the number of insemination cycles needed for reconstruction and the level of genetic relatedness in the reconstructed population. The risk for extinction was unacceptably high when a very low proportion of embryos (< 20%) was used. However, combining semen with embryos could decrease costs, allowing for the conservation of more breeds, and specific strategies for semen use could decrease the level of relationships in the reconstructed breed.     

Multiracial Facial Golden Ratio and Evaluation of Facial Appearance

This study aimed to investigate the association of facial proportion and its relation to the golden ratio with the evaluation of facial appearance among Malaysian population. This was a cross-sectional study with 286 randomly selected from Universiti Sains Malaysia (USM) Health Campus students (150 females and 136 males; 100 Malaysian Chinese, 100 Malaysian Malay and 86 Malaysian Indian), with the mean age of 21.54 ± 1.56 (Age range, 18–25). Facial indices obtained from direct facial measurements were used for the classification of facial shape into short, ideal and long. A validated structured questionnaire was used to assess subjects’ evaluation of their own facial appearance. The mean facial indices of Malaysian Indian (MI), Malaysian Chinese (MC) and Malaysian Malay (MM) were 1.59 ± 0.19, 1.57 ± 0.25 and 1.54 ± 0.23 respectively. Only MC showed significant sexual dimorphism in facial index (P = 0.047; P<0.05) but no significant difference was found between races. Out of the 286 subjects, 49 (17.1%) were of ideal facial shape, 156 (54.5%) short and 81 (28.3%) long. The facial evaluation questionnaire showed that MC had the lowest satisfaction with mean score of 2.18 ± 0.97 for overall impression and 2.15 ± 1.04 for facial parts, compared to MM and MI, with mean score of 1.80 ± 0.97 and 1.64 ± 0.74 respectively for overall impression; 1.75 ± 0.95 and 1.70 ± 0.83 respectively for facial parts. In conclusion: 1) Only 17.1% of Malaysian facial proportion conformed to the golden ratio, with majority of the population having short face (54.5%); 2) Facial index did not depend significantly on races; 3) Significant sexual dimorphism was shown among Malaysian Chinese; 4) All three races are generally satisfied with their own facial appearance; 5) No significant association was found between golden ratio and facial evaluation score among Malaysian population.     

Differences in tibial rotation during walking in ACL reconstructed and healthy contralateral knees

This study tested the hypotheses that in patients with a successful anterior cruciate ligament (ACL) reconstruction, the internal–external rotation, varus–valgus, and knee flexion position of reconstructed knees would be different from uninjured contralateral knees during walking. Twenty-six subjects with unilateral ACL reconstructions (avg 31 years, 1.7 m, 68 kg, 15 female, 24 months past reconstruction) and no other history of serious lower limb injury walked at a self-selected speed in the gait laboratory, with the uninjured contralateral knee as a matched control. Kinematic measurements of tibiofemoral motion were made using a previously-described point-cluster technique. Repeated-measures ANOVA (α=0.017) was used to compare ACL-reconstructed knees to their contralateral knees at four distinct points during the stance phase of walking. An offset towards external tibial rotation in ACL-reconstructed knees was maintained over all time points (95%CI 2.3±1.3°). Twenty-two out of twenty-six individuals experienced an average external tibial rotation offset throughout stance phase. Varus–valgus rotation and knee flexion were not significantly different between reconstructed and contralateral knees. These findings show that differences in tibial rotation during walking exist in ACL reconstructed knees compared to healthy contralateral knees, providing a potential explanation why these patients are at higher risk of knee osteoarthritis in the long-term.     

Facial image of Biblical Jews from Israel

The present report deals with reconstructing the facial shapes of ancient inhabitants of Israel based on their cranial remains. The skulls of a male from the Hellenistic period and a female from the Roman period have been reconstructed. They were restored using the most recently developed programs in anthropological facial reconstruction, especially that of the Institute of Ethnology and Anthropology of the Russian Academy of Sciences (Balueva & Veselovskaya 2004). The basic craniometrical measurements of the two skulls were measured according to Martin & Saller (1957) and compared to the data from three ancient populations of Israel described by Arensburg et al. (1980): that of the Hellenistic period dating from 332 to 37 B.C., that of the Roman period, from 37 B.C. to 324 C.E., and that of the Byzantine period that continued until the Arab conquest in 640 C.E. Most of this osteological material was excavated in the Jordan River and the Dead Sea areas. A sample from the XVIIth century Jews from Prague (Matiegka 1926) was also used for osteometrical comparisons. The present study will characterize not only the osteological morphology of the material, but also the facial appearance of ancient inhabitants of Israel. From an anthropometric point of view, the two skulls studied here definitely belong to the same sample from the Hellenistic, Roman, and Byzantine populations of Israel as well as from Jews from Prague. Based on its facial reconstruction, the male skull may belong to the large Mediterranean group that inhabited this area from historic to modern times. The female skull also exhibits all the Mediterranean features but, in addition, probably some equatorial (African) mixture manifested by the shape of the reconstructed nose and the facial prognatism.     

Analysis and evolution of water quality of the upper Váh River (northern Slovakia) by long-term changes in the community structure of ciliates (Protista: Ciliophora)

A long-term monitoring of the upper Váh River was carried out in order to evaluate evolution of water quality by means of ciliate taxocoenoses. One sampling station (Lisková) was located upstream of the pulp and paper mill in the town of Ru?omberok, while two stations (Bystrá and Stankovany) were situated downstream of Ru?omberok. Benthic samples were collected three times a year at each station during 2004–2011. This long-term study enabled us to assemble a comprehensive checklist of ciliates recorded in the upper Váh, and to characterize and compare the ciliate communities in the investigated watercourse. The saprobic index and valency analysis of the ciliate communities allowed us to quantify organic input and to evaluate changes in the saprobity of the upper Váh. The saprobic index ranged from 2.45 to 3.66 corresponding to the quality classes II–IV. Further, there was a prevalence of the α- and β-mesosaprobic levels, but during some periods the polysaprobic level increased along with the decrease of the β-mesosaprobic level. Beside the organic pollution, toxic contaminations were also noticed several times in the studied watercourse. This was documented by a significant drop in the species diversity and abundance of ciliates as well as by various morphological malformations and movement disorders of ciliates and other microorganisms. However, the negative effect of toxic and/or organic pollution wore off relatively quickly, indicating a good self-purification capability of the river.     

Effects of damping head movement and facial expression in dyadic conversation using real–time facial expression tracking and synthesized avatars

When people speak with one another, they tend to adapt their head movements and facial expressions in response to each others'' head movements and facial expressions. We present an experiment in which confederates'' head movements and facial expressions were motion tracked during videoconference conversations, an avatar face was reconstructed in real time, and naive participants spoke with the avatar face. No naive participant guessed that the computer generated face was not video. Confederates'' facial expressions, vocal inflections and head movements were attenuated at 1 min intervals in a fully crossed experimental design. Attenuated head movements led to increased head nods and lateral head turns, and attenuated facial expressions led to increased head nodding in both naive participants and confederates. Together, these results are consistent with a hypothesis that the dynamics of head movements in dyadicconversation include a shared equilibrium. Although both conversational partners were blind to the manipulation, when apparent head movement of one conversant was attenuated, both partners responded by increasing the velocity of their head movements.     

Functional MRI To Evaluate “Sense of Self” following Perforator Flap Breast Reconstruction

Background

Breast reconstruction is associated with high levels of patient satisfaction. Previous patient satisfaction studies have been subjective. This study utilizes functional magnetic resonance imaging (fMRI) to objectively evaluate “sense of self” following deep inferior epigastric perforator (DIEP) flap breast reconstruction in an attempt to better understand patient perception.

Methods

Prospective fMRI analysis was performed on four patients before and after delayed unilateral DIEP flap breast reconstruction, and on four patients after immediate unilateral DIEP flap breast reconstruction. Patients were randomly cued to palpate their natural breast, mastectomy site or breast reconstruction, and external silicone models. Three regions of interest (ROIs) associated with self-recognition were examined using a general linear model, and compared using a fixed effects and random effects ANOVA, respectively.

Results

In the delayed reconstruction group, activation of the ROIs was significantly lower at the mastectomy site compared to the natural breast (p<0.01). Ten months following reconstruction, activation of the ROIs in the reconstructed breast was not significantly different from that observed with natural breast palpation. In the immediate reconstruction group, palpation of the reconstructed breast was also similar to the natural breast. This activity was greater than that observed during palpation of external artificial models (p<0.01).

Conclusions

Similar activation patterns were observed during palpation of the reconstructed and natural breasts as compared to the non-reconstructed mastectomy site and artificial models. The cognitive process represented by this pattern may be a mechanism by which breast reconstruction improves self-perception, and thus patient satisfaction following mastectomy.     

Pathogenesis of encephaloschisis in retinoic-acid-treated hamster embryos I: a morphometric study of the craniofacial structures

The severity of the developmental disorders of the paraxial mesoderm and neuroectoderm must objectively be compared to determine which of the two structures is more deeply involved in the pathogenesis of encephaloschisis. In the present study, hamster fetuses were obtained from dams that had been treated with retinoic acid, and divided into two groups: fetuses with encephaloschisis and those without apparent external malformations in the cranium and face. Mid-sagittal serial sections of the head were prepared, histologically processed, and utilized for the reconstruction of the profile of the head structures. Using this reconstructed profile, we measured the length of the skull base bone structures (basisphenoid and basiocciput), which develop from the paraxial mesoderm, brain structures (mesencephalon and metencephalon), which develop from the neuroectoderm, and facial bone structures (nasal septum and hard palate), which develop from cephalic neural crest cells. The measured length of each structure was compared between the treated and control groups. It was found that treatment with retinoic acid resulted in significantly (P < 0.05) shortened lengths of the skull base bone structures both in fetuses with encephaloschisis and those without apparent external malformations in the cranium and face. In the brain structure of fetuses without encephaloschisis, as well as in the facial bone structures, however, this shortness was not observed. These results suggest that developmental disorders in the paraxial mesoderm may play an important role in the pathogenesis of encephaloschisis.     

Recent ecological change in a remote Scottish mountain loch: An evaluation of a Cladocera-based temperature transfer-function

Recent ecological changes in a small Scottish mountain loch, Loch Coire Fionnaraich (LCFR), were inferred using Cladocera analysis and an application of a Cladocera-based temperature transfer-function approach. Modern assemblages of Cladocera from 68 mountain lakes in Scotland and Norway were used to derive the transfer function. Among 21 measured environmental variables, mean summer lake surface-water temperature (LSWT) accounted for the highest (8%) variation in a redundancy analysis of the modern data. A quantitative inference model (r² = 0.72, RMSEP = 1.81 °C) for summer LSWT was developed using linear partial least squares regression and calibration. The resulting reconstructed summer LSWT at LCFR was compared with local instrumental air-temperature records over the last 20 yr and the Central England Temperature (CET) series over the last 110 yr. The reconstruction showed a broadly similar pattern to the local instrumental temperature records. However, the relationship between the longer CET series and reconstructed summer LSWT was poor suggesting that the site was relatively insensitive to temperature changes prior to the recent warming of the last few decades. Clear changes in Cladoceran species diversity and relative abundance of littoral taxa coincident with the most recent period of climate warming recorded both locally and in the CET suggest that Cladocera do respond to climate change. However, their response to temperature is complex and indirect. The underlying mechanism leading to change in Cladocera assemblages may involve changes in trophic status and habitat availability of the system. It is concluded that understanding other factors such as atmospheric pollution, controls of community dynamics of Cladocera and the overall ecological complexity of mountain lakes is required before any reliance can be placed on a Cladocera-temperature transfer-function for reconstructing climatic change.