Speaker verification is the biometric task of authenticating a claimed identity by means of analyzing a spoken sample of the claimant's voice. The present thesis deals with various topics related to automatic speaker verification (ASV) in the context of its commercial applications, characterized by co-operative users, user-friendly interfaces, and requirements for small amounts of enrollment and test data. A text-dependent system based on hidden Markov models (HMM) was developed and used to conduct experiments, including a comparison between visual and aural strategies for prompting claimants for randomized digit strings. It was found that aural prompts lead to more errors in spoken responses and that visually prompted utterances performed marginally better in ASV, given that enrollment data were visually prompted. High-resolution flooring techniques were proposed for variance estimation in the HMMs, but results showed no improvement over the standard method of using target-independent variances copied from a background model. These experiments were performed on Gandalf, a Swedish speaker verification telephone corpus with 86 client speakers. A complete on-site application (PER), a physical access control system securing a gate in a reverberant stairway, was implemented based on a combination of the HMM and a Gaussian mixture model based system. Users were authenticated by saying their proper name and a visually prompted, random sequence of digits after having enrolled by speaking ten utterances of the same type. An evaluation was conducted with 54 out of 56 clients who succeeded to enroll. Semi-dedicated impostor attempts were also collected. An equal error rate (EER) of 2.4% was found for this system based on a single attempt per session and after retraining the system on PER-specific development data. On parallel telephone data collected using a telephone version of PER, 3.5% EER was found with landline and around 5% with mobile telephones. Impostor attempts in this case were same-handset attempts. Results also indicate that the distribution of false reject and false accept rates over target speakers are well described by beta distributions. A state-of-the-art commercial system was also tested on PER data with similar performance as the baseline research system. / QC 20100910

<p>Biometrics is a collection of methods for identifying and authorizing individuals with something they are, or do. It is considered to be one of the most secure technologies for security, both physical and logical. Security is something very important for organizations today, but yet there has been a low interest in investing in biometrics for security in Sweden.</p><p>The purpose of this thesis has been to establish factors to why biometrics has not been implementedto any large extent, even though the technology has been around for long. We have evaluated the attitudes and views of individuals, as well as company leaders. Problem and questions with biometrics that often are discussed are privacy concerns, costs and ROI (return on investment) and user acceptance. Foremost there is a concern about the costs of implementing such a solution, although some claim that money can be saved by avoiding the costs in more traditional security methods, such as password administration and in security cards.</p><p>There is a range of different technologies to use, such as facial-scan, voice-scan and the most mature and well known technique, finger-scan which has been around for a long time, especially for identifying criminals. All these techniques have there positive and negative sides, often measured in different levels of universality, uniqueness, permanence and collectability, e.g. eye-scan has a high uniqueness, facial-scan has a high universability and signature-scan has a low permanence level.</p><p>We have collected our data through interviews with companies and suppliers of biometric systems as well as a questionnaire given to private persons. By interpreting the data in a qualitative way we have made our analysis and reached a conclusion.</p><p>Our result shows that a cost related to biometric solutions is the largest reason why investments have been absent. This verifies the results of other authors, that the cost is the largest obstacle. Another important factor is that companies believe that biometrics is for organizations with a very high security need. Further our result show that individuals are positive towards biometrics.</p> / <p>Biometri är ett samlingsnamn för tekniker som identifierar och auktoriserar individer, antingen något de är eller gör. Biometri anses vara en av de säkraste teknologierna för säkerhet, både fysisk och logisk. Säkerhet är något som är mycket viktigt för organisationer i dagens läge, men än så länge så har investeringar i biometriska säkerhetslösningar i Sverige uteblivit. Syftet med denna magisteruppsats har varit att fastställa faktorer som bidrar till att biometriska lösningar inte har blivit implementerade i någon större utsträckning, trots att teknologin har funnits länge. Vi har utvärderat individers samt företagsledares attityder och synsätt angående biometri.</p><p>Frågor och problem som ofta relateras till biometri är personligintegritet, kostnader och avkastning på investering samt användaracceptans. Framförallt är det osäkerheten kring kostnaderna av en implementering av en biometrisklösning. Det finns även de som hävdar att biometriska lösningar kan spara pengar jämfört med traditionella system därför att man undviker till exempel lösenordsadministration och passerkort.</p><p>Det finns en rad olika tekniker att använda, exempelvis ansiktsavläsning, röstigenkänning och den mest mogna och kända tekniken, fingeravtrycksläsning som har existerat en längre tid, framförallt för att identifiera kriminella. Det finns positiva och negativa sidor med alla dessa tekniker, de mäts oftast i olika nivåer av hur många som kan använda det, hur unikt biometrin är, beständighet och hur biometrin samlas in.</p><p>Genom intervjuer med företag och leverantörer av biometriska lösningar samt en utdelad enkät till privat personer har vi samlat in data. Vi har sedan tolkat data kvalitativt och utfört vår analys och slutligen kommit fram till ett resultat.</p><p>Vårt resultat har visat att kostnader relaterade till biometriska system är det största skälet till varför investeringar har uteblivit. Detta bekräftar vad många andra författare tidigare har funnit, att kostnaderna är det största hindret. En annan viktig faktor är att företag anser att biometri är något för verksamheter som kräver den allra högsta säkerheten. Vidare har individer en positiv inställning till biometri.</p>

Η δραματική μείωση του αποθέματος του χελιού (Anguilla anguilla L. 1758) σε πανευρωπαϊκό επίπεδο έχει προκαλέσει από τη μια πλευρά, αυξανόμενο ενδιαφέρον για την καλύτερη κατανόηση της βιολογίας και οικολογίας του, και από την άλλη, ανησυχία για το μέλλον του σημαντικού αυτού αλιευτικού πόρου. Ο πρόσφατος κανονισμός της Ευρωπαϊκής Ένωσης (Council Regulation (EC) No 1100/2007) επιβεβαιώνει την επείγουσα ανάγκη για άμεση λήψη διαχειριστικών μέτρων, με στόχο την αποκατάσταση του αποθέματος. Το χέλι είναι ένα είδος με μεγάλη οικονομική σημασία για την Ελλάδα, επειδή αποτελεί ένα εξαγώγιμο προϊόν υψηλής εμπορικής αξίας. Παρόλα αυτά, οι επιστημονικές μελέτες είναι σπάνιες και αποσπασματικές, τόσο στον ελλαδικό χώρο, όσο και στην ευρύτερη περιοχή της ανατολικής Μεσογείου. Ο σκοπός της παρούσας διατριβής ήταν η ανάλυση της υφιστάμενης αλιευτικής εκμετάλλευσης του χελιού και η μελέτη της δυναμικής εισόδου των νεαρών σταδίων του στα ελληνικά εσωτερικά νερά. Η περιοχή μελέτης παρουσιάζει ιδιαίτερο ενδιαφέρον, καθώς βρίσκεται στο ανατολικό όριο της γεωγραφικής κατανομής του είδους. Η ανάλυση των στοιχείων παραγωγής χελιού, που συλλέχθηκαν από το σύνολο της χώρας, δείχνει ότι οι υπάρχουσες χρονοσειρές είναι ελλιπείς, ετερόκλητες και συχνά αντικρουόμενες, οι δε παραγωγές συγκεκριμένων φορέων είναι σοβαρά υπο-εκτιμημένες. Για την ελεύθερη αλιεία υπάρχει σχεδόν παντελής έλλειψη πληροφορίας. Η δυσκολία εύρεσης αξιόπιστης πληροφορίας είναι φανερή, ακόμα και στην περίπτωση της μισθωμένης (δημόσια ιχθυοτροφεία), που υποχρεούται στη δήλωση της παραγωγής. Το πρότυπο εκμετάλλευσης εμφανίζει έντονο τοπικό χαρακτήρα με μεγάλη ετερογένεια (εντονότερο στα μεταβατικά και λιγότερο στα εσωτερικά και θαλάσσια νερά). Η αλιεία χελιού στην Ελλάδα βασίζεται κύρια στο στάδιο του ασημόχελου και είναι εποχική (Νοέμβριος-Φεβρουάριος). Από την ανάλυση των δεδομένων αποκαλύφθηκε σημαντική πτωτική τάση της παραγωγής από τις αρχές της δεκαετίας του ‘80. Η τάση αυτή συμπίπτει με την έντονη μείωση της παραγωγής των χωρών της δυτικής Ευρώπης, γεγονός, που μπορεί να σημαίνει ότι και τα δικά μας αποθέματα ακολούθησαν τις γενικότερες αλλαγές. Ωστόσο, τα δεδομένα αυτά δεν επιτρέπουν την εξαγωγή ασφαλών συμπερασμάτων, καθώς, η ποιότητά τους είναι αμφισβητούμενη και συνεπώς τα στοιχεία αυτά σε καμία περίπτωση δεν μπορούν να χρησιμοποιηθούν ως ενδεικτικά του δυναμικού της ελληνικής παραγωγής χελιού. Το πρόβλημα της αξιοπιστίας των δεδομένων είναι κοινό για τις περισσότερες χώρες της Ευρώπης και ως εκ τούτου έχει αναγνωριστεί η ανάγκη οργάνωσης ενός διεθνούς συστήματος παρακολούθησης. Για τη μελέτη της δυναμικής εισόδου των γυαλόχελων στα ελληνικά νερά, καθώς και των βιολογικών χαρακτηριστικών τους (βιομετρία και χρωματικά στάδια), πραγματοποιήθηκε πειραματική αλιεία, με τη χρήση βολκών από το 1998 έως το 2000 και από το 2001 έως το 2002. Η μελέτη έγινε σε δύο περιοχές της δυτικής Ελλάδας με διαφορετικά γεωμορφολογικά και υδρολογικά χαρακτηριστικά, στο έλος της Σαγιάδας και στις εκβολές του Αλφειού. Τα αποτελέσματα αυτά συγκρίθηκαν με τα αντίστοιχα για τον Ατλαντικό, καθώς το εύρος της παλίρροιας στη Μεσόγειο είναι περιορισμένο, σε αντίθεση με τις ακτές του Ατλαντικού, όπου έχει αποδειχθεί ότι η μετανάστευση ελέγχεται, κυρίως από τον παλιρροιακό κύκλο. Σύμφωνα με τα αποτελέσματα της μελέτης, η κύρια εποχή εισόδου των γυαλόχελων στα εσωτερικά νερά της Ελλάδας είναι μεταξύ Δεκεμβρίου και Μαρτίου (80% των συλλήψεων). Το εποχικό αυτό πρότυπο είναι παρόμοιο με εκείνο στις ατλαντικές ακτές της ΝΔ Ευρώπης, παρά τη μεγαλύτερη απόσταση των ελληνικών ακτών από τα υποτιθέμενα πεδία ωοτοκίας. Το εποχικό πρότυπο μετανάστευσης, ωστόσο, μεταβάλλεται σε μικρές χωρικές κλίμακες. Οι συλλήψεις γυαλόχελου στο έλος της Σαγιάδας αρχίζουν ένα μήνα νωρίτερα από ότι στον Αλφειό και επίσης, εμφανίζουν διαφορετικό μέγιστο, η Σαγιάδα τον Δεκέμβριο και ο Αλφειός τον Φεβρουάριο. Οι διαφορές αυτές, φαίνεται να συνδέονται με τις ιδιαίτερες τοπικές περιβαλλοντικές συνθήκες (έλος και ποταμός αντίστοιχα). Η ανάλυση των δεδομένων αποκάλυψε ότι η μετανάστευση γίνεται κατά κύματα, με περίοδο από 5 έως 40 ημέρες, και επηρεάζεται από περιβαλλοντικούς παράγοντες, όπως είναι η θερμοκρασία του νερού, η ατμοσφαιρική πίεση, η βροχή και το φως της σελήνης. Το συνολικό πρότυπο, όμως, εμφανίζεται πολύπλοκο και εξαρτώμενο από τη συνέργεια διαφορετικών παραγόντων. Το μέγεθος του γυαλόχελου (μέση τιμή μήκους: 6,02 cm ± 0,34 SD και βάρους: 0,19 g ± 0,05 SD) στις ελληνικές ακτές είναι μικρότερο από εκείνο των ατλαντικών ακτών, αλλά εντάσσεται στο εύρος τιμών που έχουν καταγραφεί για τη Μεσόγειο. Επίσης, εποχική τάση μείωσης εντοπίστηκε στο μέσο μήκος (έως 5%) και βάρος, με τη μείωση του βάρους (έως 45%) να είναι εντονότερη. Η ανάλυση των χρωματικών σταδίων (pigmentation stages) στα γυαλόχελα έδειξε εποχική διαφοροποίηση, παρόμοια με εκείνη των ατλαντικών ακτών. Αντίθετα, τα γυαλόχελα VB σταδίου (διάφανα χωρίς μελανοφόρα) αποτελούν μικρό ποσοστό (<30%) των συλλήψεων στις ελληνικές ακτές, σε σχέση με τη ΝΔ Ευρώπη, όπου κυριαρχούν (>80%) κατά τη μέγιστη άνοδό τους στα ποτάμια, υποδεικνύοντας καθυστερημένη άνοδο στα ελληνικά εσωτερικά νερά μετά τη μεταμόρφωση. Επιπλέον, τα πειράματα, που είχαν στόχο τη διερεύνηση των δυνατοτήτων εκτροφής του γυαλόχελου, που αλιεύθηκε σε ελληνικά ποτάμια, έδειξαν ότι οι ρυθμοί επιβίωσης (96%) και αύξησης (SGR 3,6) είναι ικανοποιητικοί. Η μετατρεψιμότητα της τροφής κυμάνθηκε σε φυσιολογικές τιμές για τόσο μικρά στάδια. Τα αποτελέσματα αυτά δείχνουν ότι η αλιεία και εκτροφή γυαλόχελου μπορούν να ενσωματωθούν σε ένα γενικότερο διαχειριστικό πλαίσιο για το χέλι στη χώρα. Η πολυπλοκότητα του κύκλου ζωής του είδους και η έλλειψη αξιόπιστων στοιχείων για τα χαρακτηριστικά του αποθέματος, δυσκολεύουν τη λήψη απαραίτητων (υποχρέωση εφαρμογής του κοινοτικού κανονισμού) αποτελεσματικών διαχειριστικών μέτρων, όμως, οι πιέσεις έχουν αυξηθεί και οι εμπλεκόμενοι φορείς αναγκάζονται να οδηγηθούν σε ενέργειες και αποφασιστική λήψη μέτρων. Η παρούσα μελέτη παρέχει στοιχεία, που μπορούν να αποτελέσουν τη βάση για την οργάνωση ενός συστήματος παρακολούθησης, τόσο της αλιευτικής εκμετάλλευσης, όσο και της στρατολόγησης του χελιού, σε μια περιοχή, όπου η επιστημονική πληροφορία είναι περιορισμένη. / The dramatic decline of eel stock (Anguilla anguilla L. 1758) in European waters has increased the scientific interest for a better understanding of its biological and ecological aspects as well as the concern for the future of the stock. The latest European regulation concerning measures for the recovery of the European eel stock (Council Regulation (EC) No 1100/2007), which was based on the scientific advice that the stock is outside safe biological limits and that current fisheries are not sustainable, point out the urgent need for an efficient monitoring of the eel stock at all life stages. In Greece, despite the economic importance of the species, the available biological data are scarce and limited. The aim of the present study is to analyze the current eel exploitation status as well as the glass eel migration dynamics in Greek inland waters in an area close to the eastern limit of the species geographical distribution. Towards this aim, eel production data were gathered from all official Greek authorities. Analysis of these data showed that the existing time series are insufficient, heterogeneous and usually contradicting, whereas there is almost entirely absent information concerning individual fishers. Reliable information is difficult to obtain even in cases of leased areas, such as lagoons, in which the leasing enterprises are obliged to declare their annual production. The exploitation pattern showed a pronounced regional character with great heterogeneity (more intensive in transitional and less in inland and sea waters). The Greek eel fishery is mainly based on silver eel stage and showed a clear temporal pattern (November-February). A significant decrease in eel production was observed in the 80’s. The same decreasing trend of eel production had also been observed in regions of western Europe, a fact that could signify that the Greek eel population has followed the whole changes of eel stock in Europe. However, the available data due to their limited quality do not allow reliable conclusions and consequently they cannot be used as an index of the Greek eel production. The need for an efficient international monitoring system has been recognized as this problem is common for the most European countries. In order to study the glass eel entrance in Greek inland waters as well as their biological characteristics (biometry and pigmentation stages), experimental fishing was carried out in two sites (Sagiada marsh and Alfios river - western Greece) from 1998 to 2000 and from 2001 to 2002. The two sites have different geomorphological and environmental features allowing a between sites comparison. The main period of the glass eel entrance was from December to March (80% of catches) and the migration pattern was similar to those observed along the Atlantic coast of southwestern Europe, despite the greater distance of Greek coast from the suggested spawning grounds (Sargasso Sea). However, the temporal pattern was characterized by short term fluctuations. The majority of the catches were recorded from mid November until late March in Sagiada, while in Alfios about one month later, from mid December to mid April. These differences were attributed to the specific local environmental parameters (marsh vs river). The data analysis showed that glass eel short-term freshwater migration consisted of waves with periods from 5 to 40 days and was correlated with environmental factors such as water temperature, atmospheric pressure, rainfall and moonlight. The present results showed that glass eel size (mean length: 6.02 cm ± 0.34 SD and mean weight: 0.19 g ± 0.05 SD) was smaller compared to those reported for the Atlantic coast, but similar to those reported for the Mediterranean. Mean total length and weight showed high variation and also a decreasing trend over the season (up to 5% and 45% respectively). Temporal changes were observed in the pigmentation stages of the glass eels showing a progressive increase of more pigmented individuals throughout the season, similar to those observed for the Atlantic coast. In contrary, glass eels of VB stage (‘true’ glass eel) consisted a small percentage (<30%) of glass eel catches in Greek coast in comparison to southwestern Europe where dominated (>80%) during their major ascent in estuaries indicating delayed ascent in Greek inland water after the eel metamorphosis. Moreover, a rearing experiment was carried out in order to investigate the potential of ‘greek’ glass eel rearing, showed satisfactory results. Both survival rate (96%) and specific growth rate (SGF 3.6) as well as the food conversion rate, showed normal values for such small stages. These results suggest that glass eel fishing and rearing can be integrated in an overall management scheme in the country. The complexity of eel life cycle in combination to the lack of reliable data for the stock characteristics makes difficult the enforcement of the European management measures. At the same time, the EC has increased the pressure towards this direction and the involved entities are obliged to design and receive management measures. The present study provides information that can be used as a baseline to design an efficient monitoring system of eel recruitment and also of fishery activities in a region which very few elements concerning the eel stock are available.

Šiame darbe aptariamos vartotojų internete tykančios grėsmės, susijusios su tapatybės vagystėmis. Aptariamos slaptažodžių žvejybos bei MITM atakos ir jų veikimo principai. Problemos sprendimui siūloma naudoti vieną iš biometrijos dalių - klavišų paspaudimo analizę. Pagrindinis darbo tikslas - atlikus tyrimą nustatyti, ar galima naudojant klavišų paspaudimo analizės metodą sėkmingai sumažinti tapatybės vagystės tikimybę. Pateikiami tyrimo rezultatai naudojant skirtingai veikiančias programas, naudojančias klavišų paspaudimo analizės metodą. Analizuojama, kaip klavišų paspaudimo analizės panaudojimo galimybė kinta keičiant tam tikras analizės sudedamąsias dalis. / This paper analyzes vulnerabilities that internet users face on the internet, which are related to identity theft. Phishing and MITM attacks and their principals are described. For solving this problem is suggested one part of biometrics-Keystroke analysis. Goal of this paper is to analyze possibility to reduce probability of these attacks by using Keystroke analysis. The results of using different types of programs using Keystroke analysis are presented. Analysis off how possibility of usability to use Keystroke analysis differs by changing different parts of Keystroke analysis.

Automobilių apsauga visada buvo, yra ir bus aktuali. Esamos apsaugos priemonės nesunkiai apeinamos ir nesudaro didelių kliūčių, norint transporto priemonę pasisavinti. Reikalinga naujoviška vairuotojo autentifikavimo sistema, galinti sumažinti šią, pasisavinimo tikimybę. Tam tinka biometrija – asmens bruožų ar charakteristikų statistinė analizė ir nustatymas. Juos nustačius, gali būti naudojami asmens autentifikacijai. Tai daroma lyginant su anksčiau užfiksuotu šablonu. Naudojama šioms autentifikacijoms: kompiuteriuose tinklų, praėjimo kontrolės, bankomatuose, apsipirkimams kreditinėmis kortelėmis, mobiliuosiuose telefonuose, delniniuose kompiuteriuose, medicininių įrašų valdymui, nuotoliniame mokymesi ir t.t. Pirštų kraujagyslės – nauja biometrinės autentifikacijos forma. Kadangi kraujagyslės yra po oda, jos yra nematomos apšviečiant natūralia šviesa. Tačiau jos puikiai matomos apšvietus artima infraraudoniems spinduliams šviesa. Šiame tyrime buvo sukurtas ir ištirtas biometrinės autentifikacijos automobiliams modelis. Ištirtas trijų atvaizdų apdorojimo algoritmų tinkamums, nustatant kuris jų mažiausia jautrus raiškos ir triukšmo pasikeitimams. Jį ir siūlome naudoti šiame autentifikacijos modelyje. / Automobile security is always relevant. Existing security systems could be easily bypassed and are not a big barrier for thieves. So there is a necessity for a innovative authentication system. Biometrics consist of methods for uniquely recognizing humans based upon one or more intrinsic physical or behavioral traits. In computer science, in particular, biometrics is used as a form of identity access management and access control. It could be also used for automobile security. Finger vein comparison is a relatively new form of biometrics, which could also be used for authentication. Images of finger veins could be obtained illuminating fingers with near-infrared light. Those images are very unique and different for every person and every finger. In this research biometric authentication model for automobiles is developed and researched. Three image recognition algorythms were tested in the experiment, determining which one is less sensitive to resolution changes and noise. The results were given, proposing use of one algorythm, in our model of biometric authentication system for automobiles.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Carbon monoxide (CO) is an odorless, colorless, tasteless gas that binds to hemoglobin with high affinity. This property underlies the use of low doses of CO to determine hemoglobin mass (MHb) in the fields of clinical and sports medicine. However, hemoglobin bound to CO is unable to transport oxygen and exposure to high CO concentrations is a significant environmental and occupational health concern. These contrasting aspects of CO—clinically useful in low doses but potentially lethal in higher doses—mandates a need for a quantitative understanding of the temporal profiles of the uptake and distribution of CO in the human body. In this dissertation I have (i) used a mathematical model to analyze CO-rebreathing techniques used to estimate total hemoglobin mass and proposed a CO-rebreathing procedure to estimate hemoglobin mass with low errors, (ii) enhanced and validated a multicompartment model to estimate O2, CO and CO2 tensions, bicarbonate levels, pH levels, blood carboxyhemoglobin (HbCO) levels, and carboxymyoglobin (MbCO) levels in all the vascular (arterial, mixed venous and vascular subcompartments of the tissues) and tissue (brain, heart and skeletal muscle) compartments of the model in normoxia, hypoxia, CO hypoxia, hyperoxia, isocapnic hyperoxia and hyperbaric oxygen, and (iii) used this developed mathematical model to propose a treatment to improve O2 delivery and CO removal by comparing O2 and CO levels during different treatment protocols administered for otherwise-healthy CO-poisoned subjects.

Literature has identified the need to study socially pervasive ICT in context in order to understand how user acceptability of innovation varies according to different inputs. This thesis contributes to the existing body of knowledge on innovation studies (Chapter 2) and proposes a methodology for a conceptual model, for representing dynamic contextual changes in longitudinal studies. The foundation for this methodology is the 'Price of Convenience' (PoC) Model (Chapter 4). As a theory development Thesis, it deals with two related studies of socially pervasive ICT implementation: (1) voluntary adoption of innovations and (2) acceptance of new socially pervasive and ubiquitous ICT innovations (Chapters 6 and 7).

Made available in DSpace on 2016-08-12T19:18:33Z (GMT). No. of bitstreams: 1 FabriciaNO_TESE.pdf: 1537691 bytes, checksum: 278ebea975451ffdbc330f48c2cdc61d (MD5) Previous issue date: 2014-12-12 / The pereiro-vermelho is a forest species belonging to the family Rubiaceae, considered endemic to the Caatinga and with little information in the literature, especially with regard to the morphology of seeds and seedlings, the initial stages of development and viability. Therefore, we carried out experiments in the laboratory of Seed Analysis and Morphology, anatomy, Federal Rural University of Semi-Arid, Mossoró-RN, in order to know the morphology of seeds and seedlings of pereiro-vermelho (Simira gardneriana MR Barbosa & Peixoto), as well as to assess the germination and viability of its seeds by the tetrazolium test. For the first experiment (Imbibition and morphological characterization of seeds and seedlings of pereiro-vermelho), four samples were used to evaluate 100 seeds length, width and thickness of the seeds, thousand seed weight, number seeds.kg-1, the water content, the water soaking curve, and descriptions of internal and external structures of the seeds and seedlings. The second experiment (seed germination pereiro-vermelho) was conducted in a completely randomized design, a 5 x 4 factorial arrangement, consisting of combinations of five substrates (sand between, on sand, paper roll, on paper and over vermiculite) and four temperatures (25 °C, 30 °C, 35 °C and 20-30 °C), with four replicates of 25 seeds each. In experiment (evaluation of seed viability by pereiro-vermelho tetrazolium), seeds of pereiro-vermelho were subjected to pre-wetting of paper roll for 144 hours at 30 °C and then placed in a solution of the tetrazolium 0.075%, 0.1%, 0.5% and 1.0% for 2, 4 and 6 hours at temperatures of 30 to 35 °C. The seeds were classified as viable or nonviable, according to pre-established parameters. The experimental design was completely randomized in a factorial 4 x 3 + 1, consisting of combinations of four concentrations of tetrazolium solutions, three periods of staining, and a control (germination test) for each tested temperature. Data were subjected to analysis of variance and the F test to compare the mean of viable seeds in the tetrazolium test with the results of the germination test was used were performed by Dunnett's test (p &#8804; 0.05). The thousand seed weight was 69.04 g with average dimensions of 12.72 mm long, 8.25 mm wide and 1.12 mm thick. At 25 °C, the highest percentage of normal seedlings was found on paper roll substrate, however, did not differ statistically from the other substrates, except on paper. The seeds are albuminous pereiro-vermelho, the cotyledons are foliaceous, the germination is epigeal and seedlings are fanerocotylar. Temperatures of 25 °C and 30 associated with paper roll or sand substrates are suitable for the germination test. The tetrazolium test conducted with seeds soaked for 144 h at 30 °C between paper roll, followed by extraction of the embryo and color development for six hours in solution at a concentration of 0.075% in the temperature of 35 °C is adequate to assess the viability of seeds of pereiro-vermelho / O pereiro-vermelho é uma espécie florestal pertencente à família Rubiaceae, considerada endêmica do bioma Caatinga e com poucas informações na literatura, principalmente no que se refere à morfologia de sementes e plântulas, aos estádios iniciais de desenvolvimento e a viabilidade. Sendo assim, realizaram-se experimentos no Laboratório de Análise de Sementes e de Morfoanatomia, da Universidade Federal Rural do Semi-Árido, Mossoró-RN, objetivando conhecer os aspectos morfológicos de sementes e plântulas de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto), bem como, avaliar a germinação e viabilidade de suas sementes pelo teste de tetrazólio. Para o primeiro experimento (embebição e caracterização morfológica de sementes e plântulas de pereiro-vermelho), utilizaram-se amostras de 400 sementes para avaliar comprimento, largura e espessura das sementes, peso de mil sementes, número de sementes.Kg-1, teor de água, curva de embebição em água, e as descrições das estruturas internas e externas das sementes e plântulas. O segundo experimento (germinação de sementes de pereiro-vermelho) foi conduzido em delineamento inteiramente casualizado, num arranjo fatorial 5 x 4, constituídos pelas combinações de cinco substratos (entre areia, sobre areia, rolo de papel, sobre papel e sobre vermiculita) e quatro temperaturas (25 °C, 30 °C, 35 °C e 20-30 °C), com quatro repetições de 25 sementes cada. No terceiro experimento (avaliação da viabilidade de sementes de pereiro-vermelho pelo teste de tetrazólio), as sementes de pereiro-vermelho foram submetidas ao pré-umedecimento entre rolo de papel por 144 horas a 30 °C e em seguida colocadas em solução de tetrazólio a 0,075%, 0,1%, 0,5% e 1,0% durante 2, 4 e 6 horas, nas temperaturas de 30 e 35 °C. As sementes foram classificadas como viáveis ou inviáveis, conforme parâmetro pré-estabelecido. O delineamento experimental foi o inteiramente casualizado, em arranjo fatorial 4 x 3 + 1, constituído pelas combinações de quatro concentrações da solução de tetrazólio, três períodos de coloração, mais uma testemunha (teste de germinação), para cada temperatura testada. Os dados foram submetidos à análise de variância sendo utilizado o teste F e a comparação entre as médias de sementes viáveis no teste de tetrazólio com os resultados do teste de germinação foram realizadas pelo teste de Dunnett (p &#8804; 0,05). O peso de mil sementes foi de 69,04 g com dimensões médias de 12,72 mm de comprimento, 8,25 mm de largura e 1,12 mm de espessura. A 25 °C, a maior porcentagem de plântulas normais foi encontrada no substrato rolo de papel, no entanto, não diferiu estatisticamente dos demais substratos, exceto sobre papel. As sementes de pereiro-vermelho são albuminosas, os cotilédones são foliáceos, a germinação é do tipo epígea e as plântulas são fanerocotiledonares. As temperaturas de 25 e 30 °C associadas aos substratos rolo de papel ou areia, são adequados para a condução do teste de germinação. O teste de tetrazólio conduzido com sementes embebidas durante 144 h a 30 ºC entre rolo de papel, seguido da extração do embrião e desenvolvimento de coloração por seis horas em solução com concentração de 0,075% sob a temperatura de 35 ºC é adequado para avaliar a viabilidade das sementes de pereiro-vermelho

Este estudo teve como objetivos caracterizar modificações no tamanho testicular e concentrações sanguíneas de testosterona relacionadas à idade, avaliar a presença de espematozóides epididimários, mensurar o diâmetro dos túbulos seminíferos e determinar o grau de maturação testicular, através da presença das células germinativas mais avançadas no epitélio seminífero de machos Crioulos no período da peri-puberdade. Os animais foram castrados cirurgicamente. Foi avaliada a circunferência torácica para estimativa do peso corporal. Trinta e quatro equinos foram agrupados em quatro categorias. O grupo I (GI) com quatro potros com idade de até 14 meses. O grupo II (GII) composto por sete animais com mais de 14 meses e menos de 17 meses. No terceiro grupo (GIII) foram incluídos 14 animais com mais de 17 meses e menos de 19 meses de idade e o último grupo (GIV) composto por nove equinos com mais de 19 meses e menos de 34 meses de idade. Após a castração os testículos foram pesados e medidos. Um fragmento foi coletado para posterior avaliação histológica e verificação do diâmetro dos túbulos seminíferos, além da presença de células germinativas do epitélio seminífero em diferentes fases de desenvolvimento. Uma amostra de sangue foi coletada para posterior determinação da concentração plasmática de testosterona. O peso médio dos animais no GI aumentou de 232 kg para 321 kg nos garanhões do GIV. Não houve diferença significativa entre medidas dos testículos direito e esquerdo. O peso e volume testicular apresentaram variações mais acentuadas nos animais no GIV e diferiram significativamente em relação aos animais mais jovens. Valores plasmáticos de testosterona não diferiram entre grupos e peso corporal. O diâmetro dos túbulos seminíferos apresentou variação mais marcante nos garanhões do GIV, aumentando de 89,13 μm nos potros do GI para 168,24 μm nos garanhões do GIV. Em média, 17,5% dos túbulos seminíferos não apresentaram células germinativas no GI, decrescendo para 5,4% no GII, 5,2% no GIII e 0,8% no GIV. O número de túbulos contendo espemátides maduras e espermatozóides aumentou conforme o avanço da idade dos animais. As variações mais acentuadas no incremento do volume testicular e aumento do diâmetro dos túbulos seminíferos coincidiram com a uma elevada presença de espermatozoides nos túbulos. Em conclusão, todos os animais com 20 meses de idade ou mais alcançaram a puberdade e os primeiros espermatozóides epididimários foram encontrados em potros com 16 meses. Ao testículo atingir um volume e peso testicular de 16cm3 e 23g, respectivamente, todos os animais apresentaram espermatozoides epididimários. / The objectives of this study were to characterize age-associated changes in testicular size and blood concentrations of testosterone, as well as evaluate the presence of epididymal sperm. The testicular maturity was evaluated by measuring seminiferous tubule diameter and the presence of the most advanced germ cells in the seminiferous epithelium of colts in the peri–puberty period. The animals were surgically castrated and thorax circumference was taken to estimate the body weight. Thirty four male horses were grouped into four categories: Group I (GI) with four foals aged up to 14 months; Group II (GII) with seven animals over 14 months and less than 17 months; The third group (GIII) included 14 animals over 17 months and less than 19 months; Group (GIV) was composed of nine horses over 19 months and under 34 months of age. After castration the testes were weighed and measured. A segment was collected for subsequent histological evaluation, including measurement of the diameter of the seminiferous tubules and the presence of germ cells of the seminiferous epithelium at different stages of development. A blood sample was collected for determination of plasma testosterone. The average body weight of the animals increased significantly from 232 kg in GI to 321 kg for horses in GIV. There was no difference between measures taken on right and left testes. The testicular weight and volume was greater in animals of GIV and differed significantly compared to the younger animals. Plasma levels of testosterone did not differ between age groups. The diameter of the seminiferous tubules increased from 89.13 μm in foals of GI to 168.24 μm in horses of GIV. On average, 17.5% of the seminiferous tubules had no germ cells in animals of GI, decreasing to 5.4% in GII, 5.2% in GIII and 0.8% in GIV. The number of tubules containing mature spermatids and spermatozoa increased with age. Most significant variations in the increase of testicular volume and diameter of seminiferous tubules were associated with a high presence of spermatozoa in the tubules. In conclusion all animals with 20 months of age or more had reached puberty in the present study and the first spermatozoa appeared in 16 month old colts. All animals presented epididymal sperm when testicular volume and weight were over 16cm3 and 23g, respectively.