Sergio Sánchez Cruz

Proficiency in fundamental movement skills (FMS) lays the foundation for being physically active and developing more complex motor skills. Improving these motor skills may provide enhanced opportunities for the development of a variety of perceptual, social, and cognitive skills.The objective of this systematic review and meta-analysis was to assess the effects of FMS interventions on actual FMS, targeting typically developing young children.Searches in seven databases (CINAHL, Embase, MEDLINE, PsycINFO, PubMed, Scopus, Web of Science) up to August 2015 were completed. Trials with children (aged 2-6 years) in childcare or kindergarten settings that applied FMS-enhancing intervention programs of at least 4 weeks and meeting the inclusion criteria were included. Standardized data extraction forms were used. Risk of bias was assessed using a standard scoring scheme (Effective Public Health Practice Project-Quality Assessment Tool for Quantitative Studies [EPHPP]). We calculated effects on overall FMS, object control and locomotor subscales (OCS and LMS) by weighted standardized mean differences (SMDbetween) using random-effects models. Certainty in training effects was evaluated using GRADE (Grading of Recommendations Assessment, Development, and Evaluation System).Thirty trials (15 randomized controlled trials and 15 controlled trials) involving 6126 preschoolers (aged 3.3-5.5 years) revealed significant differences among groups in favor of the intervention group (INT) with small-to-large effects on overall FMS (SMDbetween 0.46), OCS (SMDbetween 1.36), and LMS (SMDbetween 0.94). Our certainty in the treatment estimates based on GRADE is very low.Although there is relevant effectiveness of programs to improve FMS proficiency in healthy young children, they need to be interpreted with care as they are based on low-quality evidence and immediate post-intervention effects without long-term follow-up.

As science attempts to close the gap between man and machine by building systems capable of learning, we must embrace the importance of the unknown. The ability to differentiate between known and unknown can be considered a critical element of any intelligent self-learning system. The ability to reject uncertain inputs has a very long history in machine learning, as does including a background or garbage class to account for inputs that are not of interest. This paper explains why neither of these is genuinely sufficient for handling unknown inputs – uncertain is not unknown, and unknowns need not appear to be uncertain to a learning system. The past decade has seen the formalization and development of many open set algorithms, which provably bound the risk from unknown classes. We summarize the state of the art, core ideas, and results and explain why, despite the efforts to date, the current techniques are genuinely insufficient for handling unknown inputs, especially for deep networks.

PurposeWe explored the application of a machine learning algorithm for the timely detection of potential abusive head trauma (AHT) using the first free-text note of an encounter and demographic information.MethodsFirst free-text physician notes and demographic information were collected for children under 5 years of age at a Level 1 Trauma Center. The control group, which included patients with head/neck injury, was compared to those with AHT diagnosed by the Child Protective Team. Differential scores accounted for words overrepresented in AHT patient vs. control notes. Sentiment scores were reflective of note positivity/negativity and subjectivity scores accounted for note subjectivity/objectivity. The composite scores reflected the patient's differential score modified by the subjectivity score. Composite, sentiment, and subjectivity scores combined with demographic information trained a Random Forest (RF) machine learning algorithm to predict AHT.ResultsFinal composite scores with demographic information were highly associated with AHT in a test dataset. The control group included 587 patients and the test group included 193 patients. Combining composite scores with demographic information into the RF model improved AHT classification area under the curve (AUC) from 0.68 to 0.78, with an overall accuracy of 84%. Feature importance analysis of our RF model revealed that composite score, sentiment, age, and subjectivity were the most impactful predictors of AHT. The sentiment was not significantly different between control and AHT notes (p = 0.87), while subjectivity trended higher for AHT notes (p = 0.081).ConclusionWe conclude that a machine learning algorithm can recognize patterns within free-text notes and demographic information that aid in AHT detection in children.Level of EvidenceIII.

We introduce a graph neural network architecture designed to extract novel phenomena in the Standard Model Effective Field Theory (SMEFT) context from LHC collision data. The proposed infrared- and collinear-safe architecture is sensitive to the angular orientation of radiation patterns in jets from hadronic decays of highly energetic massive particles. Equivariance with respect to rotations around the jet axis allows for extracting the information on the angular orientation decoupled from the jet substructure. We demonstrate the robustness of the approach and its potential for future probes of the SMEFT at the LHC through toy studies and with realistic event simulations of the WZ process in the semileptonic decay channel.

Nonaccidental trauma (NAT), or child abuse, is a leading cause of childhood injury and death in the US. Studies demonstrate that military-affiliated individuals are at greater risk of mental health complication and family violence, including child maltreatment. There is limited information about the outcomes of military children who experience NAT. This study compares the outcomes between military-dependent and civilian children diagnosed with NAT.A single-institution, retrospective review of children admitted with confirmed NAT at a Level I trauma center was performed. Data were collected from the institutional trauma registry and the Child Abuse Team's database. Military affiliation was identified using insurance status and parental or caregiver self-reported active-duty status. Demographic and clinical data including hospital length of stay (LOS), morbidity, specialty consult, and mortality were compared.Among 535 patients, 11.8% (n = 63) were military-affiliated. The median age of military-associated patients, 3 months (interquartile range [IQR] 1 to 7), was significantly younger than civilian patients, 7 months (IQR 3 to 18, p < 0.001). Military-affilif:ated patients had a longer LOS of 4 days (IQR 2 to 11) vs 2 days (IQR 1 to 7, p = 0.041), increased morbidity or complication (3 vs 2 counts, p = 0.002), and a higher mortality rate (10% vs 4%, p = 0.048). No significant difference was observed in the number of consults or injuries, trauma activation, or need for surgery.Military-affiliated children diagnosed with NAT experience more adverse outcomes than civilian patients. Increased LOS, morbidity or complication, and mortality suggest military-affiliated patients experience more life-threatening NAT at a younger age. Larger studies are required to further examine this population and better support at-risk families.

We introduce a graph neural network architecture designed to extract novel phenomena in the standard model effective field theory (SMEFT) context from LHC collision data. The proposed infrared- and collinear-safe architecture is sensitive to the angular orientation of radiation patterns in jets from hadronic decays of highly energetic massive particles. Equivariance with respect to rotations around the jet axis allows for extracting the information on the angular orientation decoupled from the jet substructure. We demonstrate the robustness of the approach and its potential for future probes of the SMEFT at the LHC through toy studies and with realistic event simulations of the associated production of a W and a Z boson in the semileptonic decay channel.

In this chapter, we introduce real-world data in the form of RGB images and expand on the application of the underlying theory. We divide the world of images into known and novel sets and then use a sampling process to generate a large number of novelty experiments. There is a learning-based novelty-aware classification agent, but it does not actively interact with the world. For the image classification task, the perceptual operators are defined as the features computed from a Deep Neural Network (DNN) trained on the classification task using the known classes.

Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. The IEEE 802.11 standard defines the way WLANs work at the physical and medium access control (MAC) level. The recently-approved IEEE 802.11e amendment proposes a MAC protocol capable of offering quality of service (QoS) guarantees. This work has to do with EDCA (Enhanced Distributed Channel Access), which is one of the mechanisms introduced in IEEE 802.11e. EDCA promises to become a widely used protocol for terminals to gain access to services with QoS guarantees. It is then extremely important to assess its performance concerning the main QoS metrics, namely throughput, delay and losses under different traffic conditions, which is exactly the goal of this work. We obtain a set of equations by modeling the system using discrete-time Markov chains, and then validate these equations using simulations.

Abstract Objective/aim: To describe the main molecular alterations in a Colombian Cohort of patients diagnosed with Papillary Thyroid Carcinoma (PTC) at Fundacion Santa Fe de Bogota University Hospital between 1993 and 2011 Methods: A total of 231 surgically intervened patients at our institution and diagnosed with PTC with available paraffin blocks were analysed. DNA and RNA extraction was performed from FFPE samples using Quick-DNA &amp; RNA FFPE MiniPrep Kit (Zymo Research). Next Generation Sequencing analysis was performed using SOPHiA Solid Tumor Solutions Kit (SOPHiA GENETICS, Saint Sulpice, Suiza), which detects 42 DNA genes and 137 fusion genes with the platform MiSeq System (Illlumina, San Diego, California). Data underwent QA and QC and variants were analysed through Sophia commercial pipeline for somatic aberrations. Results: Among 231 patients, 82% were women, average age 45 +/- 13 y-o, 97% from Colombia, with institutional pathologic diagnosis of PTC. The most frequent histological subtypes were Classic PTG (33%), Follicular Infiltrative (29%) and Tall cell (23%). Identification of clinically relevant molecular alterations was done (see table 1). The most frequent SNV mutations were BRAF-V600E (72%), TP53 (9%) and IDH1-R132H (8%). The most frequent insertions or deletions (INDELS) were found in KIT (75%). We identified 8 fusion genes (most frequent were RET-CCD6 and ETV6-NTRK3). Interestingly, we detected 3 MSI positive cases. Conclusions: PTC molecular profile by NGS can allow us to improve molecular understanding of the disease and identify possible prognostic factors and treatment targets. Table 1. Molecular alterations detected by next-generation sequencing in Papillary carcinoma Molecular alterations Gene n % INDEL (n=20) KIT 15 75,0 NRAS 1 5,0 PTPN11 1 5,0 TP53 3 15 SNV (n=226) BRAF 163 72,1 FGFR1 1 0,4 HRAS 2 0,9 IDH1 19 8,4 KIT 2 0,9 KRAS 2 0,9 NRAS 9 4,0 PDGFRA 1 0,4 PIK3CA 3 1,3 SMAD4 4 1,8 TP53 20 8,8 Fusion genes (n=6) CCDC6-RET 2 25,0 ETV6-NTRK3 2 25,0 GOLGB1-TACC3 1 12,5 MYH14-BICC1 2 25,0 GOPC-RET 1 12,5 MSI (n=231) MSI-L 3 1,3 Negative 228 98,7 Citation Format: Paula Rodriguez, Sebastián González, Sergio Cruz, Yesith Juez, David Becerra, Margarita Baldión, Sandra Perdomo, Angela Beltran, Jose Hakim, Deyanira Gonzales. Molecular profile by next generation sequencing in papillary thyroid carcinoma, Colombian Cohort at Fundacion Santa fe de Bogota University Hospital [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6085.

A search for new physics in top quark production with additional final-state leptons is performed with 138 $\mathrm{fb}^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV. We use the framework of effective field theory to parametrize potential new physics effects in terms of 26 dimension-six EFT operators. The data are divided into several categories based on lepton multiplicity, total lepton charge, jet multiplicities, and b-tagged jet multiplicities. Kinematic variables are used to extract limits simultaneously on the associated set of Wilson coefficients.

The authors describe a rare case of mucocele of maxillary sinus and, on the basis of the histological and namely of the ultrastructural findings, they maintain that the mucocele has in all probability a multiple pathogenesis being dependent not only on the inflammatory processes, but also on other local predisposing factors and namely the active participation of the mucosa in the formation of the cavity of mucocele.

A search is presented for physics beyond the standard model in final states with two oppositesign same-flavor leptons (electrons or muons), jets, and missing transverse momentum.The data sample corresponds to an integrated luminosity of 12.9 fb -1 of proton-proton collisions at √ s=13TeV collected with the CMS detector at the CERN LHC during 2016.The analysis focuses on a search region with events containing leptons consistent with the decay of a Z boson, developing a data-driven method for the estimation of the Z+jets background based on the imbalance between the Z candidate and the recoiling jets.The observations in the signal region are consistent with the standard model expectations.

Summary Irregular landform and obstacles result in a irregular field data acquisition. However, the existing seismic data processing methods and techniques are almost based on the assumption and precondition of regularly input data. Besides, the observed seismic data always contains random noise because of impacts from acquisition equipments or the acquisition environment. Thus methods for reconstruction with the presence of noise are necessary. The simultaneous reconstruction and denoising problem can be effectively solved under the theory of compressed sensing (CS), and the projection onto convex sets (POCS) is one of the effective methods to solve the CS problem. In this abstract, we propose a damped sparse representation (DSR) based POCS method. By a introduced damping operator, the DSR based POCS method can obtain a more accurate estimation of signal, namely, a better result of simultaneous reconstruction and denoising. The feasibility of the proposed method is validated via both 5-D synthetic and field data examples.

A search is presented for physics beyond the standard model in events with two opposite-sign, same-flavor leptons, jets and missing transverse momentum in the final state. The search is performed in a dataset of 35.9 $\mathrm{fb}^{-1}$ of $\sqrt{s} = $ 13 TeV pp collisions recorded by the CMS experiment in the year 2016. The search targets models in which a colored particle is produced. Models are considered, in which a kinematic edge is observed in the dilepton invariant mass distribution and models in which a Z boson arises in the decay chain of the SUSY particles. Such searches have been performed in 8 TeV pp collisions as well as 13 TeV collisions. This version of the search adds additional event categories as well as improved background estimation procedures substantially increasing the sensitivity of the search. The results are interpreted in the context of simplified models of Supersymmetry.

A search is presented for physics beyond the standard model in events with two opposite-sign, same-flavor leptons, jets and missing transverse momentum in the final state. The search is performed in a dataset of 35.9 $\mathrm{fb}^{-1}$ of $\sqrt{s} = $ 13 TeV pp collisions recorded by the CMS experiment in the year 2016. The search targets models in which a colored particle is produced. Models are considered, in which a kinematic edge is observed in the dilepton invariant mass distribution and models in which a Z boson arises in the decay chain of the SUSY particles. Such searches have been performed in 8 TeV pp collisions as well as 13 TeV collisions. This version of the search adds additional event categories as well as improved background estimation procedures substantially increasing the sensitivity of the search. The results are interpreted in the context of simplified models of Supersymmetry.

The High Luminosity Large Hadron Collider (HL-LHC) at CERN is expected to collide protons at a center-of-mass energy of 14 TeV and reach the unprecedented peak instantaneous luminosity of $7 \times 10^{34}\, \mathrm{cm}^{-2}\mathrm{s}^{-1}$. This will allow the ATLAS and CMS experiments to each collect integrated luminosities of up to 4000 $\mathrm{fb}^{-1}$ during the project lifetime. To cope with this extreme scenario the CMS detector will be substantially upgraded before starting the HL-LHC, a plan known as the Phase-2 upgrade. The entire Inner Tracker (IT) detector will be replaced and the new detector will feature increased radiation hardness, higher granularity and capability to handle higher data rates. The detector is composed of pixel sensors with a pixel size of 2500 $\mathrm{\mu\mathrm{m}}^2$ and a new ASIC, designed in 65 nm CMOS technology, powered using a novel serial scheme. The system mechanics will be lightweight, based on carbon fiber, and will use a CO${}_2$ cooling scheme. In this contribution, we describe the design of the IT system along with the latest results on prototype system testing.

We showcase the urban, social, and technological transformation of Sixth Avenue (La Sexta Avenida) in Guatemala City, by comparing two sets of past and present-day images of the same locations newly taken and from a local photographic archive respectively. We demonstrate the value of historical-pho- to-visual practice by drawing meaning from visual and historical themes and reflective questions. We illustrate an alternative form of knowledge-making in design by developing sets of design principles informed by the meanings drawn. By coupling historical events and knowledge of present-day con- texts, the photographic pairings add another reflective dimension on present and future perspectives of design and pictorial-based research. The photographic pairings diversify our temporal and cultural sensibilities. Historical-photo-visual practice invites designers and researchers to see photographs as social documents and to consider what is revealed when the conventions and practices of past and present are in conversation.

The inclusive cross-section for tW production in proton-proton collisions at $\sqrt{s} = 13$ TeV is measured with a dataset corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected by the CMS experiment. The measurement is performed in events with one electron and one muon, and exploits kinematic differences between the signal and the dominating $t\bar{t}$ background through the use of multivariate discriminants designed to separate the two processes. The measured cross-section of $\sigma = 63.1 \pm 1.8~({\rm stat}) \pm 6.0~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is in agreement with standard model expectations.

A set of measurements of top quark pair and single top quark production in association with standard model (SM) bosons performed by the CMS and ATLAS Collaborations is presented. The consistency of these results among themselves and with the SM prediction is discussed. The latest results on four top quark production are also shown.

Os usos eficientes dos solos são problemas críticos que afetam vários países. O objetivo deste trabalho está na modelagem de um Sistema Agrícola de Próxima Geração (SAPG) para a área de Segurança de Solos. Apresentamos e avaliamos um serviço denominado do OpenSoils Edu que é parte de um SAPG voltado para gestão de dados pedológicos. O serviço é capaz de mapear grandes quantidades de dados de solos e pode ser utilizado por diversos tipos de usuários para visualização e compartilhamento de dados curados de solos.

We present measurements of the tt H and tH associated production rate performed by the CMS Collaboration in a sample of pp collision events at √ s = 13 TeV.The analyses are performed in the diphoton and multilepton channels by categorizing events according to the lepton and jet multiplicity, and to multivariate classifiers that discriminate signals from the corresponding background processes.The observed results are consistent with the SM expectations, achieving sensitivities close to five standard deviations with respect to the background-only hypothesis for tt H production.

Background: Lipodermatosclerosis, also known as sclerosing panniculitis, is a degenerative disease that affects both lower legs.This chronic condition classically affects white females in their sixties.Design: We collected 25 cases prospectively from our daily practice between September 1998 and December 2005.Patient demographics, lesional characteristics, and clinical information were gathered from submitted specimens and treating dermatologists.All biopsies were stained with H&E, von Kossa and Verhoeff-van Gieson (VVG).Results: Patient age ranged from 33 to 84 years with an mean age of 62.6 years.There was a strong female predominance with a female to male ratio of approximately 12 to 1.All lesions were present on the lower extremities, at varying sites between the knee and ankle.Lesion duration ranged from 2 months to 2 years with a mean of 9.5 months.Clinically, the lesions were described as erythematous, tender, indurated plaques or nodules.The characteristic histological findings were seen almost exclusively in the subcutaneous tissue, involving primarily the lobules but also the septa.Adipose changes included micro and macrocyst formation, necrotic adipocytes, lipomembranous change and lipogranulomas with xanthomatous macrophages.The lesions were largely devoid of inflammatory changes.Medium vessel calcification was seen in 13 cases.A conspicuous change was the presence of accumulation of basophilic elastic fibers located deep in the septa, present in all of the cases.These fibers had a moth-eaten appearance and resembled the elastic fibers of pseudoxanthoma elasticum.These fibers were positive with both the von Kossa stain and VVG in 21 of the 25 cases.Conclusions: The constellation of these histological changes is diagnostic of lipodermatosclerosis.While the pseudoxanthoma elasticum -like changes are very characteristic of this condition, they can be rarely seen in other disorders including thalassemia and calciphylaxis.

Background: Lipodermatosclerosis, also known as sclerosing panniculitis, is a degenerative disease that affects both lower legs.This chronic condition classically affects white females in their sixties.Design: We collected 25 cases prospectively from our daily practice between September 1998 and December 2005.Patient demographics, lesional characteristics, and clinical information were gathered from submitted specimens and treating dermatologists.All biopsies were stained with H&E, von Kossa and Verhoeff-van Gieson (VVG).Results: Patient age ranged from 33 to 84 years with an mean age of 62.6 years.There was a strong female predominance with a female to male ratio of approximately 12 to 1.All lesions were present on the lower extremities, at varying sites between the knee and ankle.Lesion duration ranged from 2 months to 2 years with a mean of 9.5 months.Clinically, the lesions were described as erythematous, tender, indurated plaques or nodules.The characteristic histological findings were seen almost exclusively in the subcutaneous tissue, involving primarily the lobules but also the septa.Adipose changes included micro and macrocyst formation, necrotic adipocytes, lipomembranous change and lipogranulomas with xanthomatous macrophages.The lesions were largely devoid of inflammatory changes.Medium vessel calcification was seen in 13 cases.A conspicuous change was the presence of accumulation of basophilic elastic fibers located deep in the septa, present in all of the cases.These fibers had a moth-eaten appearance and resembled the elastic fibers of pseudoxanthoma elasticum.These fibers were positive with both the von Kossa stain and VVG in 21 of the 25 cases.Conclusions: The constellation of these histological changes is diagnostic of lipodermatosclerosis.While the pseudoxanthoma elasticum -like changes are very characteristic of this condition, they can be rarely seen in other disorders including thalassemia and calciphylaxis.

The inclusive cross-section for tW production in proton-proton collisions at $\sqrt{s} = 13$ TeV is measured with a dataset corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected by the CMS experiment. The measurement is performed in events with one electron and one muon, and exploits kinematic differences between the signal and the dominating $t\bar{t}$ background through the use of multivariate discriminants designed to separate the two processes. The measured cross-section of $\sigma = 63.1 \pm 1.8~({\rm stat}) \pm 6.0~({\rm syst}) \pm 2.1~({\rm lumi})$ pb is in agreement with standard model expectations.

The degree of crystallinity (i.e., crystallite size) of agates from 11 locations on five continents was determined by powder Xray diffraction analysis.These agates formed within vesicles (gas cavities) in volcanic rocks; the ages of these rocks were obtained from the literature.The author found a strong correlation between agate crystallinity and age of the host rocks.Over geologic time, ageing allows the crystallite size to increase.Accordingly, the determination of agate crystallite size should allow an estimation of the approximate age of the host rock, which can be used to differentiate known agate deposits (since each has a unique age).The same correlation was deduced between agate density and age of the host rock.These conclusions have several potential applications.For example, an agate "artifact" purchased in Idar-Oberstein was shown most likely to have originated from Brazil rather than Germany on the basis of its degree of crystallinity and density.However, for this technique to become an accepted gemological tool, a large database with crystallinity and age data for volcanic agates and their associated host rocks, from many localities worldwide, must be developed.This method is not currently applicable to agates occurring in sedimentary rocks.KAM Bright prospects for pearl culture in India! A. K. Sonkar, Infofish International, January 2003, pp.13-16

Suele afirmarse que hoy en dia los contratos por adhesion son ubicuos. Junto a esta afirmacion es posible encontrar alguna unanimidad en la doctrina que ha examinado el tema respecto a los problemas que este tipo de negocios presentan al intentar acomodarlos dentro de las lineas de la doctrina clasica del contrato y, en conjunto con lo anterior, los potenciales conflictos que suelen presentarse desde el lado de los consumidores cuando se ven enfrentados a ellos.

A work of this type necessarily involves the cooperation and support of many people and organizations.We appreciate the cooperation of the firms involved in the field studies, and of many other colleagues and contacts as well.Many individuals assisted the field research at each company, and these individuals are acknowledged in the "source notes" that accompany the company case studies presented at the end of the book.We acknowledge here the roles of three major contributors to the overall manuscript, as well as many others who have assisted us in various ways.Professor Edwin Ruhli, University of Zurich, has had a major influence on this project from its very beginnings, and has reviewed and commented upon many of our ideas and drafts as the work has proceeded.

Amber is a fossilized form of terpenoid plant resin, the sticky substance produced by plants all over the globe.Diterpenoid resins, produced by conifers and angiosperms, are prone to polymerization and are the predominant source of amber used for cultural purposes (including gems).Triterpenoid resins, produced by broad-leaved trees, are nonpolymerizing and used as varnish resins or for incense.This study applied solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy to several hundred samples in order to characterize modern resins, fossil resins of known geological provenance, and archeological materials.Diterpenoid and triterpenoid samples were distinguished on the basis of their 13 C NMR spectra, as were changes in spectra according to age, presumably as a result of polymerization or degradation.Four major groupings of fossil resins were recognized.Group A resins spanned the globe in Cretaceous time and relate to the modern genus Agathis in New Zealand and Australia.Group B resins were widespread in Tertiary times from India to North America but are not related to specific modern plants.Group C resins, the Baltic amber group, were localized in Europe in Tertiary time but do not correspond to modern genera.Group D resins are found in the Americas and Africa and are closely related to the modern genus Hymenaea.Thus, 13 C NMR spectra can be used to determine the general provenance of archeological materials provided a sufficient sample (>30 mg) and an extensive NMR spectra database are available.

Raman spectra were obtained from natural-and treated-color (i.e., dyed and irradiated) Chinese freshwater cultured pearls, as well as Tahitian cultured pearls.The spectra were useful in identifying the dyed cultured pearls, but not the irradiated cultured pearls.Chemical analyses (by atomic absorption for 16 elements) of four of the Chinese samples (white, orange, purple, and dyed dark purple) showed no characteristic variations.Compared to the Chinese samples, chemical analysis of one Tahitian cultured pearl showed a distinctly lower Mn content (1 ppm vs. 241-643 ppm) and possibly elevated contents of Na, Sr, and Fe.WMM

Harvesting of saltwater pearls in China extends back to 200 BC, but only in the last 30-40 years have cultured saltwater pearls been farmed there.Production is mostly from the Akoya pearl oyster Pinctada imbricata and is limited to the southern provinces of Guangxi, Guangdong, and Hainan, which have suitable water temperature.The first private saltwater cultured pearl farms were established in 1986.Production grew rapidly, and by 1995 it reached ~15 tons/year.Production subsequently reached ~20 tons/year, but recently it has decreased in both quality and quantity due to several factors (e.g., environmental degradation).This article provides details of the Chinese Akoya pearl culturing and farming processes, which have many similarities to those used in the production of freshwater cultured pearls.Unfortunately, the industry now faces a number of serious infrastructure and environmental challenges.The existing farms are aging, and there is little capital available for improvements in facilities or techniques.Efforts to increase production have caused overcrowding and a further reduction in the quality of the cultured pearls.JEC Conjuring blue magic.T. Redgrave, Readers Digest (New Zealand), Vol.158, No