The Low Quiescent X-Ray Luminosity of the Transient X-Ray Burster EXO 1747-214

We report on X-ray and optical observations of the X-ray burster EXO 1747-214. This source is an X-ray transient, and its only known outburst was observed in 1984-1985 by the EXOSAT satellite. We re-analyzed the EXOSAT data to derive the source position, column density, and a distance upper limit using its peak X-ray burst flux. We observed the EXO 1747-214 field in 2003 July with the Chandra X-ray Observatory to search for the quiescent counterpart. We found one possible candidate just outside the EXOSAT error circle, but we cannot rule out the possibility that the source is unrelated to EXO 1747-214. Our conclusion is that the upper limit on the unabsorbed 0.3-8 keV luminosity is L < 7E31 erg/s, making EXO 1747-214 one of the faintest neutron star transients in quiescence. We compare this luminosity upper limit to the quiescent luminosities of 19 neutron star and 14 black hole systems and discuss the results in the context of the differences between neutron stars and black holes. Based on the theory of deep crustal heating by Brown and coworkers, the luminosity implies an outburst recurrence time of >1300 yr unless some form of enhanced cooling occurs within the neutron star. The position of the possible X-ray counterpart is consistent with three blended optical/IR sources with R-magnitudes between 19.4 and 19.8 and J-magnitudes between 17.2 and 17.6. One of these sources could be the quiescent optical/IR counterpart of EXO 1747-214.Comment: 7 pages, accepted by the Astrophysical Journa

Studi Parameter Air Dan Radioaktivitas Alam Perairan Sungai Seropan Gunungkidul

STUDI PARAMETER AIR DAN RADIOAKTIVITAS ALAM SAMPEL AIR, SEDIMEN SUNGAI SEROPANGUNUNGKIDUL. Kualitas air Sungai Seropan sebagai bahan baku air bersih (rumah tangga) harusdipantau kualitasnya melalui parameter fisik, kimia, biologi dan radioaktivitas. Telah dilakukan studikualitas air tersebut dengan parameter penelitian suhu, suspended solid (SS), radioaktivitas gross β danγ, kesadahan, COD, BOD, escherichia coli. Sampel air dan sedimen sungai diambil pada bulan Februari(penghujan) dan Agustus (kemarau) 2006. Didapat hasil pengukuran parameter kualitas air sungaiSeropan berturut-turut adalah suhu rata-rata 28˚C; SS maksimum 48 mg/L, pH maksimum 6,8;kesadahan maksimum 257,49 mg/L; COD maksimum 8 mg/L, BOD maksimum 4,9 mg/L, bakteri E. collimax > 2400 mpn/100 mL, gross b air maksimum 0,9071 Bq/L. Semua parameter tersebut masih dibawah kadar maksimum dari Keputusan Gubernur Kepala Daerah Istimewa YogyakartaNo/214/KPTS/1991 dan Keputusan Menteri Kesehatan Republik Indonesia Nomor907/Menkes/SK/VII/2002. Sampel sedimen tidak dapat dibandingkan karena belum tercantum dalambaku mutunya. Hasil identifikasi radionuklida alam pemancar gamma pada sampel air sungai adalah Tl-208 dan K-40 sedangkan pada sampel sedimen terdeteksi lebih banyak yaitu Tl-208, Ac-228, Ra-226,Pb-212, Pb-214, Bi-214, Ac-228, Ac-228 dan K-40

Development of Leucoma salicis (L.) (Lepidoptera: Lymantriidae) on Populus alba (L.) and Poplar Clone “I-214”

Σε πειραματικές επιφάνειες του Ιδρύματος Δασικών Ερευνών της Θεσσαλονίκης πραγματοποιήθηκαντο 1984 και 1985 πειράματα υπαίθρου με σκοπό τη διερεύνηση της επίδρασης της λεύκηςPopulus alba (L.) και του κλώνου "1-214", σαν υλικό εκτροφής, πάνω στην εξέλιξη του λεπι-δόπτερου Leucoma salicis (L.). Η επίδραση του φυτού-ξενιστή πάνω στο συγκεκριμένο έντομοπιστοποιήθηκε με τη βοήθεια των παρακάτω βιολογικών παραμέτρων: βάρος προνύμφης 20 και30 ημέρες μετά την έναρξη των πειραμάτων, θνησιμότητα προνύμφης, διάρκεια προνυμφικούσταδίου, συνολική διάρκεια προνυμφικού και νυμφικού σταδίου, βάρος της νύμφης, αριθμός αυγώνανά θηλυκό. Τα διάρκειας δύο χρόνων πειράματα έδειξαν μια υψηλή ανθεκτικότητα του δα-σοπονικού είδους Ρ. alba απέναντι στο φυλλοφάγο L. salicis. Σε κάθε περίπτωση, η εκτροφή τουεντόμου πάνω στο Ρ. alba είχε σαν αποτέλεσμα τη χειρότερη ανάπτυξη του σε σχέση πάντοτεπρος την εκτροφή του εντόμου πάνω σε "1-214".Tests were made to determine if the phytophagous insect Leucoma salicis (L.) (Le­pidoptera: Lymantriidae), preferred Populus alba (L.) or Poplar Clone “I-214” as its host. These tests were based on field observations in experimental plots at the nursery of the Forest Research Institute in Thessaloniki, N. Greece. The observations which continued for a two-year period (1984, 1985) corroborated the high resistance of P. alba to L. salicis. Rearing on this host-plant caused retarded growth, produced lower number of eggs, caused higher larval mortality and generally showed reduced development always, in comparison with the rearing of this insect on leaves of Clone “I-214”

Labor Law—Retail Store Owner May Deny Union Opportunity to Reply to Pre-Election Speech

N. L. R. B. v. F. W. Woolworth Co., 214 F. 2d 78 (6th Cir. 1954)

TEACHING VOCABULARY USING FLASHCARDS AND WORD LIST

The study was conducted to investigate the effect of using flashcards or word list on fifty graders’ vocabulary mastery and to discover the students’ responses toward both strategies in learning English vocabulary. This study employed a quasi-experimental research design which involved two classes, grouped into experimental and control groups with a relatively similar vocabulary mastery before treatment. The experimental group received flashcards treatment while the control group received word list treatment. The results showed that students’ vocabulary mastery improved after they were taught by using flashcards and wordlist. The students in experimental group admitted that they could memorize the words easily, be more motivated to learn English and understand vocabulary easily. On the other hand, students in the control group perceived that word list was a tedious strategy. Hence, it was concluded that flashcards is recommended to teach vocabulary to young learners.  Keywords:Vocabulary, vocabulary learning, flashcards, word list, teaching strateg

Keja L. Valens. Desire between Women in Caribbean Literature. New York: Palgrave Macmillan, 2013. vii + 214 pp.

Book Review of Keja L. Valens. Desire between Women in Caribbean Literature. New York: Palgrave Macmillan, 2013. vii + 214 pp