Freeing work from the constraints of location and time : an analysis based on data from the United Kingdom

"June 1987." "CISR WP #" appears erroneously on t.p. per telephone call to the Center for Information Systems Research (CISR), MIT.Includes bibliographical references.Lotte Bailyn

Information technology in marketing

"February, 1987." "CISR WP #" incorrectly added to t.p. per telephone call to CISR Office, MIT. -- Not part of their series. "Text of a talk given at the International Conference on Information Systems, San Diego, CA, December 15, 1986 (Revised 2/15/87)"--P. [5]Includes bibliographical referenes (p. 39).Supported in part by the Management in the 1990's Project of the MIT Sloan School.John D.C. Little

Factors invoved in onset and recovery from postnatal depression

Background: A wide variety of psychosocial variables have been implicated in the onset and recovery from postnatal depression. A number of these factors were examined on a representative sample of pregnant Maltese women attending St Luke's Hospital. Method: A random sample of 239 pregnant women were interviewed at booking using a detailed sociodemographic history, the Revised Version of the Clinical Interview Schedule (CIS-R) and Maltese translation of the Edinburgh Postnatal Depression Scale (EPDS). The CIS-R was again administered over the phone at 36 weeks and the EPDS sent by post. At eight weeks postpartum, the CIS-R, modified version of the Social Maladjustment Schedule and the EPDS were again administered to 95.8% of women. Results: Onset of depression in the postpartum was not predicted by depressive symptomatology during pregnancy, marital status, level of education, planning of pregnancy, woman's, partner's or family's reaction to pregnancy and marital adjustment. However being primiparous and employed during pregnancy were significantly associated with postnatal depression. In contrast, depressed women who remained depressed postnatally had a past personal psychiatry history and significantly higher scores on the CISR recorded at 36 weeks gestation. Limitation: The number of women examined in the study yielded a small number of depressed women, for which the results are limited in value. The sample is that of Maltese women booking in at the antenatal clinic, thus excluding women who present late, close to delivery date. The follow up period was limited to eight weeks postpartum only, excluding those who develop depressive episodes after 8 weeks. Conclusions: Some cases of postpartum depression may be traced back to pregnancy while others do not seem to be predictable during pregnancy further contributing evidence to the view that the prenatal period may be a separate entity from the postnatal period with regards to depressive illness.peer-reviewe

Constructive Multiuser Interference in Symbol Level Precoding for the MISO Downlink Channel

This paper investigates the problem of interference among the simultaneous multiuser transmissions in the downlink of multiple antennas systems. Using symbol level precoding, a new approach towards the multiuser interference is discussed along this paper. The concept of exploiting the interference between the spatial multiuser transmissions by jointly utilizing the data information (DI) and channel state information (CSI), in order to design symbol-level precoders, is proposed. In this direction, the interference among the data streams is transformed under certain conditions to useful signal that can improve the signal to interference noise ratio (SINR) of the downlink transmissions. We propose a maximum ratio transmission (MRT) based algorithm that jointly exploits DI and CSI to glean the benefits from constructive multiuser interference. Subsequently, a relation between the constructive interference downlink transmission and physical layer multicasting is established. In this context, novel constructive interference precoding techniques that tackle the transmit power minimization (min power) with individual SINR constraints at each user's receivers is proposed. Furthermore, fairness through maximizing the weighted minimum SINR (max min SINR) of the users is addressed by finding the link between the min power and max min SINR problems. Moreover, heuristic precoding techniques are proposed to tackle the weighted sum rate problem. Finally, extensive numerical results show that the proposed schemes outperform other state of the art techniques.Comment: Submitted to IEEE Transactions on Signal Processin