Hypoxia is the primary stimulus for the production of erythropoietin (EPO) in both fetal and adult life. Here, we investigated fetal plasma EPO concentrations in monochorionic (MC) twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery (UA) Doppler. We diagnosed sIUGR in presence of (1) birth-weight discordance >20% and (2) either twin with a birth weight <10th percentile. An abnormal UA Doppler was defined as a persistent absent-reverse end diastolic flow (AREDF). The intertwin EPO ratio was calculated as the plasma EPO level of the smaller (or small-for-gestational-age) twin divided by the EPO concentration of the larger (or appropriate-for-gestational-age (AGA)) twin. Thirty-two MC twin pairs were included. Of these, 17 pairs were normal twins (Group 1), seven pairs were twins with sIUGR without UA Doppler abnormalities (Group 2), and eight pairs were twins with sIUGR and UA Doppler abnormalities (Group 3). The highest EPO ratio was identified in Group 3 (p < .001) but no significant differences were observed between Groups 1 and 2. Fetal hemoglobin levels did not differ significantly in the three groups, and fetal EPO concentration did not correlate with gestational age at birth. We conclude that fetal plasma EPO concentrations are selectively increased in MC twin pregnancies with sIUGR and abnormal UA Doppler, possibly as a result of uncompensated hypoxia.

For modern management and full resource sharing among libraries and scientific departments both in Chinese and worldwide observatories, we established the computer system of library management and information retrieval during the period 1984-1987.

The system is composed of ten component sub-systems:

• 1.Book ordering system. This system can produce orders for books and periodicals, balance accounts, produce statistics as well as claims for outstanding book orders.
• 2.Book cataloguing system. This system can catalogue books under certain rules while appending new records of books to the databases. It can also produce catalogue cards and produce written reports about the new books.
• 3.Book retrieval system has the ability to search for a specific book in several ways.
• 4.Book lending or circulation system. This system is a complete circulation system; including book lending, renewals, waiting lists, and recall of borrowed books.
• 5.Periodical management system. This system is in charge of processing of periodicals and magazines in the library, including cataloguing, management, and lending.
• 6.Scientific information retrieval system. One can retrieve scientific information by keywords or in many other ways.
• 7.Internal material booking system. It can make orders of internal materials, claims for materials outstanding and make exchanges with other observatories and institutions both in or outside the country.
• 8.Internal material management system. It can do the work that is analogous to that done with books and periodicals.
• 9.Information relationship system. It handles exchanges of information between institutions. Computer system of library management ... at Shaanxl 183
• 10.Scientific information network management system. It manages affairs within a certain information network.

In this paper, first, we study the existence of the positive solutions of the nonlinear elliptic equations in unbounded domains. The existence is affected by the properties of the geometry and the topology of the domain. We assert that if there exists a (PS)c-sequence with c belonging to a suitable interval depending by the equation, then a ground state solution and a positive higher energy solution exist, too. Next, we study the upper half strip with a hole. In this case, the ground state solution does not exist, however there exists at least a positive higher energy solution.